Best Comparison Sites For Cheap Flights (2018)

Airline travel comparison sites have become a common sight across the internet.

So when it comes to looking for a cheap flight to get you out of town, there are quite a few that claim to do that job. Pretty soon, we’ll need a comparison site for comparison sites (ironic, we know).

But which website can truly find you the cheapest air fare? We did a quick look at some of the better sites to give you a headstart for your holiday.

Also, a gentle reminder - as much as such flight comparison sites can get you the best deals, don't miss out on the double bonus you get when you purchase your air tickets with the right air miles credit card

How did we pick?

For each of the airline comparison sites, we did the following:




Kayak was seldom the cheapest site. In our comparison for long distance flights, Priceline and Expedia often had options that were cheaper than Kayak by a range of $200 to $300.

Interestingly, Kayak was much more competitive with other sites when we looked up shorter routes, such as Singapore to Bangkok. Kayak came up with the second lowest prices for these flights, next to Priceline.

But Kayak has something besides prices going for it: a +/- 3-day option. You can add this option when searching for prices, and Kayak will display a table showing you alternative prices; these are the prices on the three days before your planned departure, and the three days after your planned arrival. This helps you decide on dates when you’re still planning the trip.

Kayak also has an “Our Advice” box, which tells you to buy now, watch, or buy later based on their price tracking. Assuming it’s accurate since we have no way of knowing how the algorithm works, it’s a big help in decision making.

Kayak also has hacker fares, in which you leave with one airline but come back on another. This involves buying tickets from different airlines. Hacker fares aren’t always available, but they make flights much cheaper if you can find them. We discounted this from our overall price comparison as hacker fares are erratic and available as-and-when.

Use Kayak when you are still in your early planning phase when the traveling dates are more flexible.




It’s probably not surprising that Priceline has some of the lowest flight prices for major carriers.

This site has a Best Price Guarantee. If you find a lower price after you book a ticket with them, they’ll refund you the difference. If you find a lower price after you book an Express Deals ticket with them, they’ll refund double the difference. But you must call before midnight on the day of finding the lower price for the Express Deals ticket. For regular tickets, you have 24 hours to call.

The Express Deals option is one of the unique selling points, which pulls up flights with up to a 50% discount. However, you won’t have exact details about the flight until your itinerary arrives. That mean you won’t know the carrier, the number and duration of layovers, or your exact time of departure and arrival. The good news is, Priceline guarantees that no layover will exceed three hours.

Great for the budget conscious but definitely not for control freaks who want to plan every step of their trip.

One important thing to note is that Priceline does not include budget airlines. As such, it won’t have the cheapest tickets for short flights, which can be covered by lower cost carriers.

Without the use of Express Deals, the only other sites that seems to match Priceline (for long flights) are Momondo and Skyscanner. Between the three, Priceline often comes out cheaper by at least $40 to $60 for long trips.

One annoying issue though: there were a few times when Priceline sent us to the booking site, and we found that the price was higher than the one quoted on Priceline.

Use Priceline for long-distance flights which are typically more expensive and harder to get discounts for.




First off, Expedia has about a billion tie-ins with credit cards. Both the UOB PRVI Miles American Express Card and UOB PRVI Miles World Mastercard have Expedia promotions. At present, every dollar spent on an Expedia booking gives you 6 bonus miles.

Expedia also has an extensive rewards programme with three rewards tiers:

The points can be used for special deals to get vouchers for hotel stays or redeem flights. Note that the points accumulation can be stacked with your credit card rewards.

When used to book a complete package (flight, car and hotel), and used repeatedly over time, Expedia could save you more than the other sites on this list. But if you’re not a frequent traveller, and don’t care to spend time accumulating reward points, you might want to look elsewhere.

Use Expedia if you are planning for long term rewards accumulation.




Still the king of the budget flight, Skyscanner was the first comparison site to include budget airlines.

Their strategy hasn’t changed much over the years: Skyscanner finds you the cheapest flights, period. It’s a formula that works.

Skyscanner searches over 1,200 airlines to compare prices, making it probably the most comprehensive airline comparison sites. There’s also a cool “everywhere” button, which straight up lists the cheapest flight tickets to a bunch of random destinations. Perfect if you have a holiday budget, but aren’t sure where to go.

There isn’t much else to say about Skyscanner, other than use it if price is the main concern.

Use Skyscanner for the overall cheapest air fares.




Momondo has the best user interface among all the sites on this list. In fact, it may have the best user interface of any travel-based site ever.

When you book a flight on Momondo, you also get a visual calendar showing you probable prices on alternative dates. For example, when booking from 1 to 14 June, we could also check prices if we were to leave between 27 to 31 May or arrive between 15 to 28 June. However, online reviews suggest that these prices may not be quite as accurate as Kayak.

Momondo can also rank flights on a scale of 1 to 10. The shorter the flight’s duration and the lower the price, the higher the rating. The algorithm also factors in details such as arrival times (it’s assumed you don’t want to arrive at 4am, for example) to decide the overall ranking. For travellers who don’t want to spend hours comparing a dozen details, you can use this as a one-click system to get the best deal.

Momondo also promises that you remain anonymous to them – no tricks like using your web browser’s cookies to monitor your visits and gradually raising the prices.

Momondo was often able to beat other comparison sites in terms of fares; it even has a function that lets you compare it to other sites, such as Momondo versus Expedia. It wasn’t always the cheapest however, with Priceline often matching it for long flights on major carriers, and Skyscanner often beating it by around $70 to $120.

But there’s one glaring issue.

Sometimes, we clicked on a flight option from Momondo, only to discover the flight was priced differently at the site we were led to. In some instances, the flight wasn’t even available. There seems to be some lag in Momondo’s real time tracking of different sources.

But don’t let that fool you. This is still one of the first sites you should check.

Use Momondo for the ease of usage and often affordable prices.