Regardless of your travel experience, it can be overwhelming to choose the best flight search engine. Airfare sites each work differently, and they all have dedicated user bases. To find the best flight search engine, we compared the most popular travel search engines and flight finders. Here are our top five flight search engines.
Best flight search engines 2020
1. Best cheap flight search engine: Skiplagged
One of the reasons Skiplagged is able to find cheap flights is that it exploits a loophole in airline ticketing. Instead of searching only for tickets from City A to City B, it also searches for "hidden-city" tickets — flights from City A to City C that have a layover in City B. For example, let's say you need to get to Chicago. If you search for a flight from New York to Chicago, Skiplagged may find a cheap flight from New York to Denver that has a layover in Chicago. You can simply get off the plane in Chicago, without completing the entire flight pattern.
While rumors swirl that this is practice is illegal, it is not. However, airlines have been reported to retract airline miles from those who regularly do this.
One drawback to using Skiplagged is that it doesn't have an option to filter by class or to search specifically for premium economy, first- or business- class tickets. The website will automatically filter your search results by price, which means that economy-class tickets, that are typically cheaper, will always be at the top of the results page.
2. Best multi-city flight search engine: Google Flights
Google Flights is our runner-up due to its excellent search experience and its consistent retrieval of competitively priced tickets on any itinerary we entered. One of the best features of the service is that it allows you to search for flights across multiple airports with one query. For example, if you're booking a flight to Charlotte, N.C., and you're not sure whether you'll be in Boston or New York, Google Flights will let you browse departures from both cities with one search.
Speedy load times and sleek interface
Of the sites we evaluated, Google Flights without fail returned results the quickest across dozens of queries. Search results on Google Flights consistently loaded in under a second, while other sites – e.g., Hotwire and Priceline – took much longer. Another benefit is both the mobile and desktop versions of the service provide an intuitive and familiar interface for people who already use Google apps.
Save money by booking each leg separately
One of the reasons Google finds inexpensive itineraries is that it allows you to book the departure and return legs of your trip on different airlines. This is helpful in cases where booking two one-way tickets is more affordable than booking a round trip. While Google Flights didn't invent this concept (sites like Kayak have long offered a mixed-airline itinerary), we found that it was nicely integrated into the service's search capabilities.
3. Best international flight search engine: Momondo
Compared to the other airfare sites we evaluated, Momondo performed the strongest when searching for international itineraries, particularly business-class tickets. Momondo works by searching for tickets on online ticket agencies – Momondo doesn't sell tickets on its own website – which allows it to find low prices on third-party services.
Book through third-party Online Ticket Agencies (OTAs)
Most of the sites that we evaluated allow users to book tickets directly on their platform or on the airline's website. Momondo only lets you book tickets through OTAs, meaning you'll have to complete the sale on a website that may be unfamiliar to you, like Flights Mojo, Globehunters or TravelMint. This shouldn't be an issue in most cases, but it can present a problem if you need to change or cancel your flight (some airlines charge more to change a ticket bought through an OTA).
Mediocre search experience, interface and site speed
Compared to our top two picks, Momondo's user experience is a bit lacking. Google Flights loaded its search results significantly faster than Momondo, and Skiplagged's interface had a much cleaner and more modern feel. In general, we recommend using Skiplagged and Google Flights for domestic bookings and Momondo only when searching for international flights.
4. Best European flight search engine: Skyscanner
Skyscanner has an outstanding platform to search for flights in Europe. You can also search for hotels and rental cars on the site using its seamless tab integration. It has decent load times, a clean user interface and includes plenty of European airlines in its listings, like Lufthansa and Air France. You can also select different flight classes, which makes Skyscanner a great business-class search engine.
5. Best search engine for flights in the USA: Agoda
Agoda provides users with a simple user experience to grab their travel necessities quickly. They are owned by the same parent company as Priceline, Kayak and Booking.com, so you can rest assured your booking is with a legitimate business.
In addition, Agoda offers Agoda Homes, which is their own proprietary homestay service. Comparable to Airbnb, many consumers may find it handy to book their flights and unique homestay experience on the same website.
Honorable Mentions for best flight search engine
Kayak is a tried-and-true flight search option that has quick load times and solid travel packages for hotels, rental cars and cruises. While it didn't perform as well as Momondo on international flights, it found the same affordable domestic business-class itinerary as Google Flights. If you're looking to book a travel package or domestic flights, Kayak is an excellent option.
For domestic tickets and trips to the Caribbean, the Southwest Airlines website is a must-visit destination. Southwest offers affordable tickets across its route map — and it doesn't allow its tickets to be sold or displayed on third-party websites like Skiplagged, Google Flights and Momondo. As such, you should always check Southwest before booking a domestic economy or Caribbean itinerary on another airline.
How to get cheap flights, regardless of which search engine you use
Even the most-advanced flight search engine can only get you so far. If you want to save money on airfare, your best bet is to plan ahead. Follow the tips below to maximize your savings:
Earn travel rewards from credit cards
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Fly on a Tuesday or Wednesday
If possible, book the departure and return dates of your trip in the middle of the week, as Tuesdays and Wednesdays are the cheapest days to fly. Flights are more expensive on the weekends and on Mondays and Fridays. If you have flexibility when you fly, most of the search engines we recommended allow you to view prices for flights on each day of the week.
Book two months in advance
Studies suggest that 54 days ahead of your desired travel window is the cheapest day to book tickets for an upcoming trip. While you don't have to be this exact, it's strongly advised to buy tickets at least two months before you plan to fly. Prices start increasing after the two-month mark and skyrocket two to three weeks before the departure date.
Take your trip in off-peak season
There are certain times of year when it's much more expensive to fly — think major holidays, long weekends and your state's school vacation weeks. If you have the flexibility, you can save hundreds by planning your vacation around these busy travel dates and booking your trip off-peak, especially if you're flying to a seasonal destination like Hawaii.