Which travel site should you turn to when booking plane tickets: a) Travelocity, b) Expedia or c) Orbitz? The answer is d) All of the above by using Kayak, a meta-search site for travelers. Kayak scours more than 100 search engines in order to find the lowest possible price. One tip: before you buy from any travel site, always check Southwest. It's the one major airline that refuses to play ball with the ticketing sites, so sometimes they have the best deal and even Kayak doesn't know about it.