Four giant airline computer systems in the United States handle nearly all the airline reservations in the country. (They're known as CRSs, for computer reservations systems, or more often now GDS for global distribution systems.) Although each airline has a ``home'' CRS, the systems are all interlinked so that you can, with few exceptions, buy tickets for any airline from any CRS. The dominant systems in the U.S. are Sabre (home to American and US Airways), Galileo (home to United), Worldspan (home to Delta, Northwest), and Amadeus (many European lines.) The company that owned Galileo and Orbitz recently bought Worldspan, so the two GDS will presumably be merged. Many of the low-price start-up airlines don't participate in any of these systems but have their own Web sites where you can check flights and buy tickets. Southwest, the largest and oldest of the low-price airlines, doesn't participate, either. Southwest's web site gets car and hotel info from Galileo, but the info seems not to flow the other way. Orbitz one of the big three online travel agencies, runs its own system which is "direct connect" linked directly to many of the airlines. 

This ultra-modern terminal complex features the Midfield Terminal Building, one of the most architecturally impressive structures in the Middle East and the third largest airport terminal in the world. The building will offer exclusive entertainment, vibrant landmark lounges, modern guest rooms, world-class cuisine, and an up market duty free area with high end retail outlets and designer brands from all over the world. 
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