American scraps 900 more flights Thursday

— -- American Airlines canceled more than 900 flights Thursday to inspect potentially faulty wiring, marking the third straight day of mass groundings as company executives offered profuse apologies and travel vouchers to calm angry customers.

American, the nation's largest carrier, has now scrubbed more than 2,400 flights since Tuesday, when federal regulators warned that nearly half its planes could violate a safety regulation designed to prevent fires.

That's more than one in three flights canceled over the last three days. Daniel Garton, an executive vice president of American, said cancellations could extend into Friday, especially if forecasted thunderstorms and heavy rain Thursday further disrupts American's operations at Dallas-Fort Worth Airport, its largest hub.

A return to normal operations depends on how quickly mechanics can inspect and fix the wire bundles.

American estimates that more than 100 passengers would have been on each of those canceled flights. That means a quarter-million people have been inconvenienced this week.

In a press conference Thursday afternoon, American Airlines CEO Gerard Arpey took personal responsibility for the cancellations. They could cost the company "tens of millions of dollars," he said.

With the Federal Aviation Administration increasing its inspection efforts, Arpey declined to predict if the carrier would cancel more flights beyond this week. "The FAA is stepping up surveillance to do their job. These audits aren't something we anticipated a month ago."As of Thursday morning, American Airlines said it had cleared 80 MD-80s to resume flying.

Dan Garton, American's executive vice president for marketing, apologized repeatedly to travelers Wednesday at a news conference at the airline's Fort Worth headquarters.

He also announced that in addition to providing food, lodging and ground transportation vouchers for affected travelers, American is giving those stranded overnight vouchers good for $500 in future travel on American. Travelers who did not get those vouchers initially can apply for them on the carrier's website, aa.com.