Passenger information goes into the system and tells gate workers whether all the passengers have ar

DALLAS (AP) -- American Airlines played catch-up Wednesday, federal travel regulations resuming most flights and even adding a handful that were not on the schedule to help passengers stranded by a massive technology failure that grounded the carrier's entire U.S. fleet.
As you'd imagine, we do have redundancies in our system, Tom Horton, chief executive of parent company AMR Corp., said in an apology posted on YouTube. federal travel regulations But unfortunately in this case, we had a software issue that impacted both our primary and backup federal travel regulations systems.
American federal travel regulations and smaller-jet subsidiary American Eagle said Wednesday night that they canceled 475 flights but that most were due to bad weather and only 81 related to technical federal travel regulations issues. However, United and Southwest had roughly half as many cancellations as American, and other major airlines had even fewer, according to flight-tracking services.
Still, American's performance was a huge improvement over Tuesday, when the computer trouble brought all departures to a halt for several hours. American and Eagle canceled federal travel regulations nearly 1,000 flights and delayed another 1,100. Two-thirds of their scheduled flights were late or never took off.
As marooned passengers resume their travels, questions lingered about the technology and whether American's systems will be adequate to avoid similar collapses after the company merges with US Airways to form the world's biggest airline.
Money has been tight for airlines in recent years, so spending has been focused on immediate needs rather than upgrading technology, said Ira Gershkoff, who runs SlipStream Aviation Software federal travel regulations and has worked as a technology executive for Polar Air Cargo, travel technology company Sabre and at American Airlines.
AMR and US Airways hope to complete the merger by September and create a giant that would surpass current industry leader United in passenger miles. Airline mergers are always difficult, and one of the trickiest parts is combining technology systems.
When the systems of US Airways and America West Airlines were combined in 2007, chaos ensued. Hundreds of check-in kiosks didn't work, ticket agents were swamped, and flights delays lingered for days.
Even if flights federal travel regulations operate on time, there can be other hitches when systems are merged. At United, upgrades for elite members of the frequent-flier program weren't handled properly, and flights booked with miles weren't always ticketed correctly. Those mistakes were especially upsetting to the airline's most loyal customers. It's one thing for one flight to be late. For many veteran fliers, it's worse to constantly worry about upgrades.
Airline technology is notoriously complicated because so many pieces of the system rely on each other for information, said Emre Serpen, a consultant at InterVistas who works with airlines on technology issues.
Passenger information goes into the system and tells gate workers federal travel regulations whether all the passengers have arrived. The same information is used to calculate the weight of the fully loaded plane. Flight dispatchers, who may be in a command center across the country, use the figures to order the right amount of fuel -- too much fuel adds weight federal travel regulations and reduces mileage.
Besides performing many functions, airline computer systems might be assembled or serviced by different vendors. For American, the complexity will be magnified when it combines reservations, scheduling, frequent-flier and other programs with those at US Airways.
They have to merge all the data from US Airways over to the American federal travel regulations system. There could be huge translation problems if the two airlines' systems federal travel regulations use different coding, said Bill Curtis, senior vice president of CAST, a business federal travel regulations software-analysis firm.
AMR did not immediately respond to a request to make its chief information officer, Maya Leibman, available for an interview. She has been American's top technology officer for a little more than a year, replacing an executive who resigned shortly after AMR filed for bankruptcy protection in November 2011.
The term information federal travel regulations technology appeared only three times in AMR's latest annual report filed with the Securities and Exchange Commission, and the company has provided few details on how much it spends to improve and maintain its computer systems, or who does all the work.
AMR said in the annual report that it has engaged an increasing number of third-party service providers for many jobs, including information technology hardware and services. The report also said the company will spend at least $80 million this year and $70 million in later years on a single IT-support contract.
US Airways CEO Doug Parker will run the new company after the merger. He has said he would prefer to convert his company's computer systems to American's since American is larger. He has pointed to the technology federal travel regulations breakdowns that occurred after the United-Continental and US Airways-America federal travel regulations West mergers, when the larger airline adopted the smaller one's systems.