Last July, 14 months after United and Continental Airlines announced they were combining to form the largest carrier in the world, the merged airline took one of the thousands of steps required to integrate its fleet: It harmonized the coffee. If one wants to blame someone when United flight is canceled, blame Jim DeYoung. He oversees the consolidated network operations center, a NASA-style command room in Elk Grove Township on the outskirts of Chicago. The team's biggest headache in the merger, however, has been combining flight information systems. Along with labor negotiations, information technology (IT) tends to be the thorniest part of an airline merger. Last August the ops center's functional integration team decided that legacy United's flight information system, Unimatic, would be better able to handle the size of the merged airline's fleet than Continental's.