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Booking a Flight

December 10, 2021 (Last updated: December 15, 2021)


Booking a Flight Online

With the increasing relaxation of the travel restrictions that were imposed because of the COVID-19 pandemic, more and more people again are travelling by airplane. There is no shortage of options to book a flight online. The issue is how to use these options most effectively to find the flight that best meets your needs. This article examines the dos and don’ts of booking a flight online.

When searching for an airline ticket online, you can do so through an online travel agency (OTA), a flight search engine, or directly through an airline's website. For each option we have described the advantages and disadvantages. Regardless of whether you use an OTA, a flight search engine, or an airline company website, you will also find several tips for booking a flight online.


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1. Online Travel Agencies (OTAs)

2. Flight Search Engines

3. Booking directly

4. Use an OTA, Flight Search engine or book directly?

5. Setting Price Alerts

6. Book early or last minute?

7. Our Favorite Flight Search Engines

8. Our Favorite Online Travel Agencies (OTAs)

9. Our Research


Online Travel Agencies (OTAs)

One option to book a flight online is to use an online travel agency (an “OTA”). An OTA is a website that sells flights online and functions as a middleman between airline companies and consumers to help consumers buy airplane tickets. We've researched the following most used OTAs on the internet.



Priceline is one of the most widely used OTAs in the US. The Priceline website is easy to use, and you can filter your searches by ‘Round-trip’, “One-way’, and ‘Multi-destination’. Priceline also lets you easily book an entire trip by combining flights with hotels, cars, and cruises.



Expedia Flights

With Expedia you can easily book flights, yet Expedia's strength lies in bundling services together. You can easily plan a full trip on Expedia, as you can search for ‘Stays’, ‘Cars’, ‘Packages’, “Things to do’, and ‘Cruises’, in addition to flights.




Travelocity has been around since 1996 and is a well-known name in the online booking world. The website is part of the Expedia Group, as are Hotwire and Orbitz. You can easily combine your flights with other travel options - ‘Packages’, ‘Stays’, ‘Cars’, “Cruises’, and ‘Things to do’. If you're looking for a good package deal, Travelocity is a great way to save some money.




Unlike most other major OTAs, CheapOAir is a privately owned company. And it shows in the website, which has its own unique character. Based on the name, you might think that this website mainly offers cheap airline tickets, but as we have seen in our research, the different services are difficult to distinguish based on price. So if you are looking for the lowest price for a ticket, it is best to try the different services yourself for your specific search, because the lowest price varies from case to case. There is no clear winner when it comes to the lowest price for tickets.




Orbitz is a major player in online travel. Like Travelocity, Orbitz is part of the Expedia Group. As a result, the search results are very similar. In addition to flights, you can book hotels, cars, cruises, things to do (including tours and day trips) and travel packages on Orbitz.




Onetravel is part of the same company as CheapOair. Therefore, the websites are very similar, and the search results are also very alike.




Just like on most of the other flight websites, with Kiwi you can also search flights by ‘Return’, ‘One-way’, ‘Multi-city’, and ‘Nomad’ (finding the best itinerary for multiple destinations). You also can search flights by ‘Economy’, ‘Premium Economy’, ‘Business’, and ‘First Class’ (and even by ‘mixed classes’). The Kiwi website also highlights refund and cancellation options. is of course known as a hotel booking site, but you can also easily book flights on its platform. Searches for flights can be filtered by 'Round-trip', 'One-way', and 'Multi-City', and by 'Economy', 'Premium economy', 'Business', and 'First-class'. In addition to flights, allows you to book hotels, rental cars, attractions, and airport cabs. We think is the best booking site for hotels, so if you want to combine a flight with a hotel booking, is a solid choice.




Hotwire is a pretty good service for finding cheap hotel rooms and combining them with flights, but we think there are better alternatives for that task. For example, at Orbitz and Expedia you can receive additional benefits through their rewards programs. However, Hotwire often offers great deals through their Hot Rate Deals. However, if you are purely looking for an airline ticket you are better off using other services.


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Flight Search Engines

A second option to book a flight online is using a flight search engine. Unlike an OTA, a flight search engine is a website that cannot be utilized to book a flight directly. Instead, it is used as a tool to research flight alternatives. For example, once you have found your best flight choice, Kayak or Momondo will connect you to another website to actually book your flight. We have researched the following frequently used flight search engines.


Google Flights

Google Flights helps you to easily schedule airline trips. You can filter your searches for flights by ‘Round trip’, ‘One way’, or ‘Multi-city’ and by ‘Economy’, ‘Premium economy’, ‘Business’, or ‘First’.




Founded in 2003, Cheapflights is now managed by KAYAK. CheapFlights claims to ‘work with more than 300 partners to bring you better travel deals’ (including OTAs and airline companies). At the Cheap Flight website, you also can search for ‘Vacation packages’, ‘Hotels’, and ‘Car rental’.




Skyscanner lets you research and book travel options for your trips, including flights, hotels and car hire. You can search for flights by ‘Round trip’, ‘One way’, or ‘Multi-city’. You also can add “nearby airports’ in your searches and search only for ‘Non-stop flights’ or ‘Flexible tickets’.




Momondo has a colorful website and a fast, user-friendly interface. Momondo offers about the same filtering options that other flight search engines also offer. Since the site's launch in 2006, it has received excellent reviews. For example, Momondo ranked second in a 2021 survey by Frommer's. According to them, it is one of the best places to find the cheapest airline tickets, especially for last-minute tickets. You can filter your searches by ‘Round-trip’ or ‘One-way’ and search only for ‘Nonstop’ flights. You also can book hotels, car rentals, attractions (‘things to do’), vacation packages, and trains through Momondo. Momondo is part of the same company as, Kayak, and Priceline. Not surprisingly, the search results are very similar.



Kayak is one of the most widely used flight search engines. Their search engine functionality works quickly and is easy to use. Kayak offers a ‘Price Freeze’; for a small fee, you can have the benefit of getting the current price if the price subsequently increases or the lower price if the price subsequently decreases.



According to Frommer's, Skiplagged is the price champion. However, from our research, there is no standout in terms of lowest price. Still, we see Skiplagged being praised more often for their search results. Skiplagged uses a slightly different search technique than the other services. The Skiplagged website highlights for you ‘Hidden-City’ flights (a flight when you get off at a layover point, rather than at the final destination) to save money. For example, a flight from New York to Los Angeles might cost $400, but a similar flight from New York to Seattle with a stopover in Los Angeles might cost $300. When you go to Los Angeles, Skiplagged shows you both flights, and if you choose the cheaper flight, you get off the plane at the stopover (Los Angeles) instead of going to the final destination (Seattle).


Booking directly

A third option for booking a flight online is to use an airline company website. Before OTAs and flight search engines, an airline company website was the traditional method to book a flight online. When you go to the American Airlines website, you can both research and book the best American flight that fits your objectives. For an easy outline of all major airlines visit our visual overview of the largest airlines in the U.S.


TipWith a little flexibility in dates, you can save a lot. Most booking websites allow you to check off that you are flexible on dates. This allows you to explore more flight alternatives and also find cheaper flights.


Using an OTA, Flight Search engine or booking directly

The lowest prices in our research were offered by both flight search engines, OTAs and airline company websites. So, there is no way to be sure that a certain type of website will always have the lowest price. In addition, it is important to note that most of the flight search engines and travel agency websites are built on the same underlying search engines, such as ITA, Sabre en Amadeus. Therefore, most websites also tend to offer the same results and prices. Also, many websites are owned by the same parent company, so search results are very similar. For example, Travelocity, Hotwire and Orbitz are all part of the Expedia Group. However, there are other reasons to determine which website is best to use, as described below. Later in this guide we will also reveal our favorite websites based on criteria such as usability, speed of search results, filtering options, overall user experience and more.


OTA vs Flight Search Engine

One commonsense perspective favors OTAs over flight search engines. It seems more efficient to use an OTA than a flight search engine. With an OTA, you research and buy your flight all on one website; with a flight search engine, you research your flight on one website and buy your flight on another website. Moreover, in some cases flight search engines have problems in properly connecting to an airline's website.


OTA vs Booking Directly

Another common sense perspective favors OTAs over booking directly via airline company websites. With an OTA, you are searching over many different airlines so you can compare them based on your preferences. These benefits suggest a general preference for OTAs. In fact, OTAs offered the lowest price in most of our sample bookings.


Advantages of booking directly

There can be certain advantages to booking your flight through an airline company website.

First, when you book a flight in the United States at least seven days in advance through an airline company website, you generally have the right to cancel or change the flight within 24 hours of booking. With certain exceptions (Priceline, Expedia, Travelocity, and Orbitz all have certain cancellation policies), OTAs do not offer this “24-hour cancellation” policy.

Second, an airline generally will provide better customer service than an OTA. Thus, if liberal cancellation policies and a higher level of customer service are important to you, you may want to consider booking your flight through an airline company website.

One approach is to use an OTA to find the best flight for you and then compare its price with the price offered for the flight on the applicable airline’s website. If the price difference is small, you may want to book the flight on the airline company’s website to receive the benefit of a “24-hour cancellation” policy and better customer service. We've carefully selected the most used airlines in the U.S.


TipBe aware of the search term you use in researching the flight. Particularly with “dropdown” choices, it is easy to pick only a single airport in a city and miss out on potential flights. For example, for Washington, D.C., if you inadvertently select "Reagan National Airport", you can miss international flights in and out of "Dulles International Airport".


Setting Price Alerts

Price alerts can be an effective tool to book a flight when its price comes down to an amount in your budget. If you are planning a trip and have flexibility as to when you will travel, price alerts can be useful and can save you lots of money.

If you have the flexibility, it is also prudent to check the effect of varying your travel dates by one day, either earlier or later. A one-day difference in the flight you book possibly can result in a significant savings in price.


Booking early or last minute?

It is generally better today to book a flight in advance as early as possible than to wait for the last minute to book a flight. If you wait until the last minute to book a flight, the flight could be sold out.

There was a time when flights would drop in price at the last minute to stimulate demand, but as many flights in 2021 are fully booked or even over-booked, there is less incentive for the airlines to lower prices at the last minute.

Nevertheless, if you need to book a flight at the last minute, sometimes there will be “last-minute discounts” on the websites, so it is always prudent to check if any are available.


TipThe prices on the various websites include taxes and certain fees. However, they do not include other charges, including for baggage. You should always determine all of the charges that you expect to incur before booking your flight.


Our favorite Flight Search Engines

As became clear from our research, the search results differ slightly from moment to moment and from situation to situation. There is no clear winner in terms of the lowest price. There is no winner in this area. However, we do have favorites based on their usability, website speed and other factors.


Google Flights

Everything we have come to expect from Google, the user friendliness and speed of their main search engine and other services, can also be found in their flight search engine, Google Flights. The entire user experience is focused on finding the best flight as quickly as possible. In addition, you can find fares from some of the major OTAs such as Expedia and Orbitz. Compared to the other search engines, Google provides the most options and features to filter search results. To help you make more sustainable travel choices, you can even check carbon emission estimates on your flight.

We have tried all the major flight search engines using different test bookings, from a usability perspective Google Flights is without a doubt the most robust tool for finding airline tickets.




Next to Google Flights, Kayak is one of our favorite flight search engines, largely because the great user interface, price transparency, fast search results, and because you can tweak your search preferences endlessly. You can also filter on flight quality, like whether Wi-Fi is available. You can even filter on Aircraft model. Not only can you get the best and cheapest flights fast, but you can also set up price alerts. Kayak will then keep you up-to-date via email and/or push notifications, letting you know when’s the right time to book.


Our Favorite Online Travel Agencies (OTAs)

We've compared the different OTAs based on several test bookings. As became clear, there is no guarantee that a website always will offer the lowest price. For example, in terms of comparing individual websites, both Onetravel and Cheapoair were at the top (lowest price) and at the bottom (highest price) in different sample bookings. And besides, if there is a difference in price at all, they are often minimal differences. However, based on other criteria we can say that these are our favorite OTAs.


Expedia Flights

If you want to book a flight combined with a hotel and rental car, Expedia is the place to go. With the right bundle deal, booking a flight on Expedia is definitely worth it. Another big advantage of using Expedia is their loyalty program, which allows you to collect and redeem points on flights, rental cars, activities and more. So, the more often you travel the more favorable it becomes to book through Expedia. Their loyalty program has three levels - Blue, Silver and Gold - that allow you to get upgrades and special amenities. For example, you'll earn points in addition to your airline miles and credit card rewards. Besides potential discounts by bundling, you can also easily add travel insurance that covers the entire trip, like a flight cancellations plan, hotel booking protection plan and more. Above all, we love Expedia for the ease of using their website, the ability to bundle services, and the wide choice of hotels.

To conclude, Expedia is a great service for those who travel often and want to bring together various parts of their trip into one convenient and cost-effective booking. is mostly known for their great hotel booking service, but you can also book flights very easily through their platform. Like on Expedia, you can easily book different parts of your trip together on, like airport taxis, attractions, car rentals and more. is our absolute favorite for booking a hotel. If you are looking for a flight combined with a hotel booking then is the way to go.


Our Research Approach

To determine the relative strengths and weaknesses of the above-described individual websites and different types of websites, we made several test bookings. In the example below you can see how these tests were conducted.

* For each test booking, we researched the above-described 15 OTAs and flight search engines. We also checked the airline websites for the airline(s) that appeared to offer the lowest price from the OTAs and search engines.

* Only flights at reasonable times (i.e., not with takeoffs very early in the morning or very late at night) were considered.


Booking Examples - Price Comparisons


Example 1

From Major City to Major City

Proposed Flight:

Departs from Chicago to Los Angeles on Monday, November 29, 2021/Returns from Los Angeles to Chicago on Wednesday, December 1, 2021/Economy/Nonstop 

Kayak had the lowest price - $370.79 – for a departing flight on Spirit Airlines (“Spirit”) at 1:35 pm, and a returning flight on United Airlines (“United”) at 4:50 pm. 

These flights available on Priceline, Expedia, Google, Travelocity, Orbitz, and Skyscanner for more than the Kayak price, but less than $380.

These flights available on Cheapoair, Cheapflights, Momondo, Kiwi, Booking, and Skiplagged, but the price was more than $380.

On Onetravel and Hotwire, the departing flight was the same, but the returning flight was different – a Spirit flight at 2:30 pm. The price for these flights on both Onetravel and Hotwire were in excess of $450. 

None of the Spirit, United, nor Southwest websites offered a price below $450.

Winner: Kayak


Example 2

From Major City to Significant City

Proposed Flight:

Departs from New York to Milwaukee on Monday, November 29, 2021/Returns from Milwaukee to New York on Wednesday, December 1, 2021/Economy/Nonstop  

Skiplagged just barely had the lowest price - $316.40 – for a departing flight (from Newark) on United at 6:15 pm, and a returning flight (to Newark) on United at 9:40 am.

Each of Priceline, Kayak, Expedia, Google, Travelocity, Orbitz, Cheapflights, Momondo, and Hotwire had these flights available for a price of $316.80.

Booking had these flights available for $317.25, and Cheapoair, Skyscanner, and Onetravel had these flights available for varying amounts in excess of $330.

The Kiwi website could not be accessed for this example.

United had these flights available for $316.80.  Southwest does not offer a nonstop flight between New York and Milwaukee.

Winner: Skiplagged


Example 3

From Significant City to Significant City (long flight)

Proposed Flight:

Departs from Seattle to Orlando on Monday, November 29, 2021/Returns from Orlando to Seattle on Wednesday, December 1, 2021/Economy/Nonstop

The lowest price was offered by Delta Airlines (“Delta”) - $506.80 – for a departing flight at 8:35am, and a returning flight at 6:05pm. Google, Skyscanner, and Onetravel had these flights for a higher amount, varying between $566.80 and $589.99.

Priceline and Cheapflights had a price of $561.80 for the above-described Delta departing flight and a returning flight on Alaska Airlines (“Alaska”) at 5:55pm.

Orbitz, Travelocity, Expedia, Skiplagged, and Hotwire each had these Delta and Alaska flights for a higher price, varying between $566.76 and $581.80.  

Booking and Cheapoair offered higher prices ($597.42 and $623.99, respectively) for a departing flight on Alaska at 9:00am and the above-described Delta returning flight.

On both Kayak and Momomdo, when it connected to the Delta website, it changed the travel dates to a different date.

The Kiwi website could not be accessed for this example.

Alaska had the above-described Alaska flights available for $621.80. Southwest does not offer a nonstop flight between Seattle and Orlando.

Winner: Booking directly via the Delta Airlines website


Example 4

From Significant City to Significant City (short flight)

Proposed Flight:

Departs from Phoenix to Dallas on Monday, November 29, 2021/Returns from Dallas to Phoenix on Wednesday, December 1, 2021/Economy/Nonstop

Both Onetravel and Cheapoair offered the best price - $152.99 – for a departing flight on Frontier Airlines (“Frontier”) at 6:32pm and a returning flight on Frontier at 5:04pm.

These flights were available on Skiplagged for $217.50 and on each of Skyscanner, Google, Momondo, Kiwi, Kayak, Expedia, Travelocity, Orbitz, Hotwire, Priceline, and Cheapflights, for prices ranging from $232.00 to $247.98.

Booking had two different flights on American (departing at 7:40 pm and returning at 2:01pm) for $304.80.

On the Frontier website, the above-described Frontier flights were available for $237.96.

The American website had the above-described American flights for $305.

The Southwest website had flights in excess of $350.

Winners: Onetravel and Cheapoair


Example 5

From Significant City to Small City

Proposed Flight:

Departs from Las Vegas to Ithaca, New York on Monday, November 29, 2021/Returns from Ithaca, New York to Las Vegas on Thursday, December 2, 2021/Economy/Only One Stop (No Nonstop Flights)

The best price was offered by both Travelocity and Orbitz - $764.39 for a 12:39pm departing flight on American (with a stop in Charlotte), and a 3:14pm returning flight on American (again, with a stop in Charlotte). Kayak and Expedia were just behind in price at $764.40 for these flights.

These flights were also available on Priceline, Google, Cheapoair, Cheapflights, Skyscanner, Onetravel, Momondo, Booking, Skiplagged, and Hotwire at prices ranging from $807.39 to $937.40.

Kiwi offered the above-described American departing flight, with a returning flight at 3:42pm on Delta (with a stop in Detroit) and then Spirit, for a price of $872.

American had the above-described American flights on its website for $918.

Delta did not offer a departing flight at any reasonable time.

Spirit and Southwest have no flights to Ithaca.

Winners: Travelocity and Orbitz


Example 6

From US City to International City

Proposed Flight:

Departs from Washington, DC to London on Monday, November 29, 2021/Returns from London to Washington, DC on Tuesday, December 7, 2021/Economy/Nonstop

Kiwi had the best price - $680.16 for a 5:55pm departing flight on United, and a 12:05pm returning flight on United.  

Booking and Skyscanner had the next best prices for these flights, both below $700, followed by Priceline, Kayak, Expedia, Travelocity, Orbitz, Cheapflights, Momondo, Hotwire, Cheapoair, Skiplagged, and Onetravel, all below $730.

The highest price for these flights was offered by Google at $810.50.

United on its website offered the price of $693.37 for these flights.

Southwest does not have flights to London.

Winner: Kiwi


Example 7

From International City to International City

Proposed Flight:

Departs from Paris to Madrid on Monday, November 29, 2021/Returns from Madrid to Paris on Wednesday, December 1, 2021/Economy/Nonstop

The best available price was offered by Onetravel - $182.60 for a departing flight on Air Europa at 10:05am, and a returning flight on Air Europa at 4:50pm.

Kayak, Google, Skyscanner, Momondo, and Skiplagged had these flights for prices between $240 and $250.  Priceline, Expedia, Travelocity, Orbitz, Cheapflights, Kiwi, Booking, and Hotwire had these flights for prices between $250 and $264.

The most expensive price for these flights was from Cheapoair - $295.60.

Air Europa, on its website, offered these flights for $264.

Southwest does not have flights to Paris or Madrid.

Winner: Onetravel