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Disaggregating fare aggregators 2009: Which airfare comparison sites are the best?

Nearly three years ago, this site reviewed the then-burgeoning field of airfare aggregators, also known as metasearch sites. These sites let you compare the fares available across multiple airlines and across multiple booking sites, to help you find the lowest fare. Last time, Kayak came out on top. How much has changed in the last three years?

For starters, there are sites which have folded, some new competitors, and sites that changed their model significantly. At the same time, there has been pushback from airlines and suppliers, some of which have resisted the aggregator model. (The lawsuits between American Airlines and Kayak, which initially resulted in American Airlines no longer being listed in Kayak results, was perhaps the most prominent case of pushback. Since October 2008, results are back in the results. More on that below.)

The result: The golden ring of a truly complete search, covering all the options and all the providers, is still a ways away. No single site actually finds every flight option, every fare, or every seller.

But that doesn’t mean that there aren’t differences between the aggregators. It’s time to disaggregate the aggregators again.

This year, each site was put through multiple tests. Four kinds of itinerary were tested: A large-city to medium-city domestic US flight with multiple carriers offering direct service; a medium-city to small-city domestic US flight with at least one change of plane required; an international flight with a US origin; and international flights (from Paris to Dubai, and Manchester to Madrid) to test how sites do for non-US flights. For each of these flights, I tested a short-term booking (7 days advance purchase) and a longer-term booking (30 days advance purchase).

This time, I compared Kayak, Sidestep, Mobissimo, TripAdvisor Flights, Momondo, Skyscanner, WeGo (formerly Bezurk), Trax, Farecast,, and Dohop. Sites which were on the list last time but either folded or stopped doing metasearch include FareChase (bought by Yahoo, then abandoned in March 2009), PriceGrabber, and Qixo.

So which aggregator came out on top in 2009? Here’s the summary, with site-by-site reviews thereafter…

  • Overall best bet: TripAdvisor Flights. Low fares, good features, a solid performer overall. It took them a while to join the game, but it’s a strong product with a small but important edge over its closest competitor, Kayak.
  • Lowest price, domestic: If you’re searching for domestic US airfare, most of the aggregators did pretty well, but the lowest fares were consistently on TripAdvisor Flights, Mobissimo, or Momondo. (Kayak and Sidestep would have been included in this list, but they often offered the lowest flights at the same base fares, but typically directed you to Orbitz, instead of to the airline or to a no-fee site like Priceline, to buy the ticket. Orbitz still charges a booking fee as of this writing, so single-airline itineraries can typically be purchased for less elsewhere.)
  • Lowest price, international from US: If you’re searching for international flights starting in the US, try Kayak and Trax.
  • Lowest price, international, ex-US: If you’re search for international flights that don’t originate or end in the United States, Mobissimo and Momondo performed best.
  • Class conscious: If you’re looking for a deal on premium cabin fares, is your site.
  • Sorting features: If you want control over options, and like to tweak and limit your results, Kayak gives you the most power.
  • Real total cost: TripAdvisor Flights lets you estimate what your actual costs will be, including luggage checking fees, headphone charges, etc.
  • Avoid: WeGo, which offered impressively-low search results, but none were actually bookable. Also avoid Dohop, whose prices were consistently higher than their competitors.

Individual site reviews

TripAdvisor Flights

Although a clone of its competitors in many respects, TripAdvisor’s new aggregator offers one big difference: The site offers an analysis of how much the flight will actually cost you, once you figure in the baggage fees, the headphone fees, etc. It even considers what your elite status is. That’s a great feature. Second, and more disappointingly, the site (unsurprisingly) favors its sister sites Expedia and Hotwire in its results. But those sites add no booking fee right now, so no big whoop. The site combines the best sorting features of Kayak with the added value of fee analysis. TripAdvisor takes it by a nose.


Kayak is the largest of the metasearch sites, and it offers solid results. But it didn’t consistently offer the cheapest fare, because the universe of sites it searches is sometimes limited by agreements with individual partners. (American Airlines, for example, won’t allow results from its website to be shown alongside AA flights sold through Orbitz.) Orbitz puts demands on its partners, too, and subsequently, Kayak is heavily Orbitz-centric, with no representation of Expedia, Travelocity, or Priceline. Actual fare availability was good when I clicked through to sellers’ sites. Kayak’s sorting features are still the best (so good that they’re copied wholesale by TripAdvisor), with the ability to narrow search results by time, airline, or aircraft type (e.g., no props or RJs), to name a few. The site has recently added “flight quality warnings,” such as on-time percentages and tight-connection alerts, but those aren’t a big deal.


Kayak bought Sidestep a few years ago, but continues to operate the site as a standalone entity. Frankly, I don’t see why. The results are identical, the search tools are nearly the same, and there’s nothing to recommend this site over its parent. Everything stated above is true here as well, but why bother?


Farecast, now owned by Microsoft, is most famous for their fare prediction engine, which suggests whether ticket prices for your route will drop in the future. The predictions are pretty accurate, though they don’t account for times of day, routing, or airline, if you have preferences on those matters. (And you should.) Farecast also offers up an aggregator, albeit a fairly minimalist one with few options and a favoritism for Orbitz results. Come here for the fare predictions, but for live fare comparisons, you’re better off elsewhere.


Mobissimo claims to search more sites than anyone else, but not necessarily for a domestic US search. They have good coverage of Asian and European airlines, but their controls and filters are less than others’. Decent results, but I preferred others’ display of information.

From the folks who brought you TravelZoo, offers one gimmick that’s worth noticing: First- and business class fare comparison. That’s it. Otherwise, it’s a clone of other sites. If you’re not looking for premium cabin seats, skip it.

WeGo (formerly Bezurk)

Big on teasers, low on success. WeGo touts some amazing fares, but good luck buying them. They also don’t list the lowest flight first: They show a sponsored link at the top. Bad, bad, bad.

Update April 9, 2009: WeGo has eliminated the sponsored results feature.


Britain’s SkyScanner offers decent results for UK-based searches, but it’s not as helpful to others. For US and non-UK searches, SkyScanner searches returned far higher fares than the average.


This Danish site is quite good at ferreting out obscure sellers of travel, especially for intra-European itineraries. But be aware that you’ll often get results from suppliers in countries outside the destination or origin. Flying Chicago to Baltimore? Your ticket could be sold by a British company (which could mean a 3% credit card surcharge).


Update December 2009: Trax has retrenched, and is no longer touting their fare comparison as their primary product. Their homepage shows a disclaimer as of December 7, 2009. But their search engine is still up and running if you dig for it… This is odd, to say the least. offers a Kayak-lite search that works well for domestic US itineraries. They include Priceline and Cheapoair, which others don’t, but the results weren’t significantly better.

Two other sites of note:

1. An aggregator you can’t use for booking, but which is great for research, remains ITA Software. Their engine powers Orbitz, and backs up Kayak and TripAdvisor results. They’re a great resource. (Click “log in as a guest” to use the search without registering.)

2. No discussion of fare search would be complete without a mention of FareCompare. The site’s alerts give you a heads-up on future sales by notifying you when fares drop, before they go on sale. They offer fare search, too, which is powered by Kayak.

So… what’s your experience with fare aggregators? Hit the comments to share your stories.