Kayak is a metasearch engine for flights, hotels, and car rentals. They are headquartered in Stamford, Connecticut, but have a large office in Los Angeles, California.
Priceline is an online travel agency based in Norwalk, Connecticut. They offer cheap flights, hotels, and vacation packages.
Orbitz is an online travel agency based in Chicago, Illinois. They have a large office in San Francisco, California.
Travelocity is an online travel agency based in Southlake, Texas. They have a large office in San Francisco, California.
