DALLAS —  American Airlines canceled more than 1,000 flights Wednesday, more than one-third of its schedule, as it spent a second straight day inspecting the wiring on some of its jets — the same issue that caused it to scrub hundreds of flights two weeks ago.

The nation's biggest airline had already canceled 460 flights on Tuesday, stranding thousands of travelers. Federal inspectors found problems with wiring work done two weeks ago, although the airline says passenger safety was never jeopardized.

Airline officials said the flights would have averaged more than 100 passengers, meaning that more than 100,000 travelers could have been left scrambling to book new flights.

The cancellations could continue to the end of this week as the airline works on its fleet of 300 MD-80 jets. By Wednesday morning, only 30 of the planes were back in service.

American uses the MD-80s mostly on mid-range flights, particularly from hub airports in Dallas and Chicago. Wagner said 208 of Wednesday's cancellations would occur at Dallas-Fort Worth International Airport and 138 at Chicago O'Hare.

At New York's LaGuardia Airport, hundreds of passengers stood in a check-in line. The airline offered free doughnuts, coffee and orange juice, but there were few takers.

Bishop Bernard Jordan, a Harlem minister, was in a first-class line trying to catch a flight to Atlanta, where he was scheduled to preach Wednesday night.

"It would have been good to know in advance," said Jordan, who said he has 4 million frequent-flier miles with American and flies to Atlanta every other week. "I would have booked with another airline."

At Dallas-Fort Worth, Mike Barnes was wearing the same clothes he had on Tuesday morning when he left San Diego for a business trip to Indianapolis. The trip was interrupted by the sudden midday announcement of cancellations, leading Barnes to call the airline "totally unprepared."

"If it was safe enough to fly from San Diego to Dallas, why isn't it safe enough to fly from Dallas to Indianapolis?" asked the 53-year-old information technology consultant.

The airline issued a fresh apology Wednesday from Gerard Arpey, the chief executive of American and its parent, AMR Corp. Arpey said American "will do whatever it takes" to help affected customers, including compensating those who stayed overnight somewhere other than their final destination.

The Fort Worth-based carrier said it would put displaced travelers on other American flights or those operated by competitors. Wagner said that because the delays were "within our control" and not weather-related, American was offering meals, lodging and ground transportation to those affected.

American operates about 2,300 daily flights, more than one-third with MD-80s.

It was American's second bout with mass cancellations in less than two weeks for failing to meet the same wiring rules set by the Federal Aviation Administration, which is cracking down on airlines after admitting its inspectors were too lax last year with Southwest Airlines Co.

Since the FAA began looking more closely at airlines' compliance with safety directives, there have been cancellations at Southwest, Delta Air Lines Inc. and UAL Corp.'s United Airlines. The agency levied a $10.2 million civil penalty against Southwest for using planes that had missed inspections for cracks in the fuselage.

This week, FAA inspectors looked at 19 of American's planes and found that 15 violated regulations on bundling of wires in the wheel well, said FAA spokeswoman Diane Spitaliere. According to American, the issue revolves around the spacing and direction of cords used to secure bundles of wires in the planes' auxiliary hydraulic systems.

The airline said flight safety was never compromised, but began yanking planes out of service around mid-afternoon Tuesday so that wiring bundles could be inspected and stowed properly in the wheel wells.

The cancellations and resulting loss of revenue could hardly come at a worse time for American, which is facing high fuel prices and a weakening economy that could hurt demand for travel.

AMR is scheduled to report first-quarter earnings in two weeks, and analysts are forecasting a loss of more than $300 million, according to a survey by Thomson Financial.

Jamie Baker, an analyst with JPMorgan, said in a recent note to clients that he expects airline revenue to decline significantly beginning in the April-June quarter due to the one-two punch of costly fuel and a possible recession.