DALLAS — American Airlines and Delta Air Lines canceled hundreds more flights Thursday as they continued inspections of wiring bundles on some of their planes.

Although thousands of passengers were inconvenienced over the past two days as the airlines inspected their MD-80 planes, analysts downplayed any notion that the cancellations would hurt the airlines financially. They said the costs would pale in comparison to high fuel prices.

Delta expected to cancel about 275 flights, or about 3 percent of its schedule, before returning to normal operations early Friday, said spokeswoman Chris Kelly.

No flights were affected at Delta's Salt Lake City hub, said Delta spokesman Anthony Black. "We don't fly the MD-80s to or from Salt Lake."

American, the nation's largest airline, canceled 141 flights by midafternoon Thursday, or about 6 percent of its estimated 2,300 flights, officials said. The Fort Worth-based airline canceled 318 flights Wednesday.

At American, inspectors from the airline and the Federal Aviation Administration focused on fixing the spacing between cords used to secure bundles of wires in the auxiliary hydraulic systems of its MD-80 aircraft.

"In no way was safety compromised, but the (FAA) directive said 'Do it this way,"' said American spokesman Tim Smith.

American completed inspections and in some cases alterations on 269 MD-80s by midafternoon, and another 21 were still undergoing work that was expected to be done Thursday, Smith said. Nine planes remained to be inspected Thursday night, he said.

Smith said American found seats for most passengers on other planes but also put some customers on other airlines' flights.

The largest number of cancellations, 42, were departures from Dallas-Fort Worth International Airport, with another 22 departures scrubbed at Chicago O'Hare, Smith said. Flights from those airports are more likely to use MD-80s, while some airports, such as Miami, were barely affected, he said.

Delta expected heavy volumes Thursday at its hub at Hartsfield-Jackson Atlanta International Airport, Kelly said. Both Delta and the Transportation Security Administration were bringing in extra staff to handle the crowd of travelers, she said.

The inspections came almost three weeks after the FAA ordered a check of maintenance records at all U.S. airlines, following criticism of the agency's handling of missed fuselage inspections at Dallas-based Southwest Airlines Co.

The FAA imposed a $10.2 million civil penalty on Southwest this month for missing the inspections and then continuing to fly the planes with passengers on board even after realizing the mistake. Southwest officials have said they repaired small cracks in the fuselages of six planes last year and four this month.

The FAA said it would check compliance with at least 10 safety orders at every U.S. airline by Friday. A more complete audit is due by the end of June.

The airlines declined to detail how much they were losing on canceled flights and extra inspections and maintenance.

Contributing: Laura Hancock, Deseret Morning News.