Some questions and answers about the impact of the bankruptcy filings by Delta Air Lines Inc. and Northwest Airlines Corp.:

Q. Why did the airlines file for bankruptcy now?

A. They have been squeezed hard by high labor and jet fuel costs, and each has lots of long-term debt hanging over its head, including underfunded pension plans. And on Oct. 17, changes in bankruptcy law will make it harder for companies to cancel their debts.

Q. What happens to passengers?

A. Probably not much. Both airlines promised to honor all tickets already issued. But the airlines are free to change schedules and cut routes, however. Anthony Sabino, a business professor at St. John's University in New York, said there could be some service disruptions.

Q. Will frequent-flier miles be affected?

A: "No, not unless they want to commit suicide with their customers," New York bankruptcy lawyer William Rochelle says. With past bankruptcies, the airlines have done their best to honor frequent-flier plans. But, Sabino says there is no certainty about bonus and promotion programs. "Due to the need to cut costs, that is something that will no doubt be examined and probably modified to some extent," Sabino says.

Q. How will employees be affected?

A. They'll be in a much weaker position. A bankruptcy judge could void labor contracts and impose layoffs, pay cuts and work rule changes. The airlines could ask the court to impose the sorts of concessions they have been trying to negotiate with the unions, or they could seek even deeper pay and job cuts from the court.

Q. What will be the effect on the airline industry?

A. At this point, it is another chapter of bad news on top of other bad news. "After decades of airlines big and small filing for bankruptcy, the shock value is gone," Sabino says. Rochelle says he believes "a successful reorganization, especially including lower wages, will present a major competitive threat for the other network carriers with higher costs."