When building a travel itinerary or planning a vacation, make Kayak (free) your first stop. Kayak has the best search interface for complex travel needs and cross-checks other sites to make sure you get the lowest price for the trip you want. Kayak is our Editors' Choice among travel search sites. Its primary limitation is that it's meant more for search, not pre-paying for reservations, although that's slowly changing as Kayak strengthens partnerships that allow for some credit card transactions right on its site. Still, when Kayak finds the best deal possible, it will send you directly to the airline's site, or Orbitz (4.5 stars), Expedia (3.5 stars), or wherever you need to go to buy what you want.

If you'd rather get the whole enchilada in one sitting, stick with Orbitz, as it's by far the best for start-to-finish travel planning and booking, from search to credit card processing to guaranteeing you got the lowest possible price (among its other customers, that is). But really, you can only benefit by hitting up Kayak first because it will scour the Web for the lowest price, which may or may not come from Orbitz, and Kayak's search criteria options are slightly more refined.

The Basics
Like all travel search sites, Kayak starts with a list of options at the top for what kind of travel you might want to search: flights, hotels, cars, deals, vacations, and cruises. The flight panel has tick boxes to let you add hotel and car rental to that search for a possible combo deal. These options are standard for the big players, such as Orbitz, Expedia, and Travelocity (3.5 stars). They're missing from a few niche sites, including Google Flights (3 stars), which only searches air travel, and Hipmunk (3.5 stars), which focuses solely on flight and hotels. a name="video">

Kayak's Standout Features
Before you even initiate the search, Kayak shows you on a calendar the least expensive dates to fly to your destination. This predictive advice isn't always available, especially when the dates of travel are too far in the future, but when it does appear and your dates are flexible, it's a god-send. In fact, more "flexible date" options are available right from the initial starting screen, from which you can look for reservations plus-or-minus three days of the selected date, for all weekend travel, or for any dates within a "select month" (e.g., four to five nights for any 35-day period you select, and I have no clue why it searches 35 days instead of 30 or 31, but it does and I don't have a problem with that). For holiday planning in particular, you can't beat Kayak's flexible search options.

From the bottom of that first search page, you can tell Kayak to search Priceline, Travelocity, Expedia, and any other travel booking sites or specific airlines that have flights along your route. Search for a flight from New York to Quebec City, and Air Canada pops up as an option. Need to fly from Heathrow to Rome? CheapOair and OneTravel are added to your possible selections. Opting to search these additional sites opens them in new windows, which can clutter the screen, but it rather advantageously lets you do the ultimate in price-comparison shopping.

Once you initiate a search that includes a flight, Kayak does a wonderful job displaying the results. A snippet of the flight details appears to give you an overview of the price, carrier, departure and arrival times, as well as any layovers. Clicking on any result opens it so you can see the complete details without leaving the main results page.

Another amazing and helpful inclusion on Kayak is a Price Trend box that shows up on the upper left corner of the screen, telling you whether to buy or wait, based on whether Kayak thinks the fare will increase and confidence level of its prediction. If you see a deal and aren't sure if you can do better, Kayak's advice comes in handy.

Yet another way to get the best price is to set up a fare alert (or two or three), which Kayak prompts users to do from time to time while you're on the site. With fare alerts, Kayak sends you a message (email, text message, whatever you prefer) when a flight price reaches a threshold that's acceptable to you, or it can spit out an automated email with the latest prices daily or weekly.

Finally, when refining a search that includes flight options, the adjustments you can make to refine your search are better and more detailed than you'll find on Orbitz.

More Than Flights
Kayak searches much more than just flights, with sections for cruises and vacation deals based on your geographic region according to what you establish in your Kayak account—although you can change it if you want a last-minute deal starting from somewhere else. You can also scout around for deals based on interest, such as family-friendly vacations, beach getaways, and so forth.

The hotel booking section of Kayak is on par with its flight search, although it doesn't go as far as travel search site Hipmunk in terms of helping you find exactly what you want, if what you want isn't a straight hotel room. Hipmunk includes results from Airbnb as well as HomeAway, two websites offering house and apartment rentals from individuals rather than companies.

While Kayak users have not traditionally been able to book directly on the site, being sent off to another provider for anything that requires a credit card, Kayak has added some functionality to process payments in conjunction with partners. In my recent testing, I only came across this feature in the hotels and car rentals sections, and the processing page had a small logo at the top, indicating the partner involved (Travelocity, Budget, etc.). I'm sincerely looking forward to seeing Kayak expand its ability to let users book right on the site. With flights added, it would make the Kayak experience simply phenomenal.

Kayak's Best Foot Forward
Turn after turn, Kayak seems to anticipate what it is you might possibly want, and delivers tools for you to find it. Its search options are better than any other travel website's, and additional advice, like wait-versus-buy recommendations for airfare and automated price alerts, elevate the site well beyond travelers' basic expectations. And now that Kayak has some limited capabilities for letting users book on-site, its service is positioned to get even better. Kayak is PCMag's Editors' Choice for travel search. It should be your first destination every time you plan to travel.

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