The federal government on Thursday announced flight restrictions coinciding with public ceremonies at the three Sept. 11 crash sites.

The temporary rules are less stringent than those presented to the aviation industry last week. That proposal would have banned internationally owned commercial airlines from flying over the sites on the anniversary of the terrorist attacks.

"Our concerns with the initial proposal were that the foreign airlines were discriminated against," said Wanda Warner, spokeswoman for the International Air Transport Association, which represents U.S. and foreign-owned airlines. "The revised program does not do that."

While restrictions on flight patterns for all commercial aircraft could cause some delays on Sept. 11, "it's certainly better than the operating ban," she said.

International agreements governing landing rights specify that foreign airlines not be discriminated against.

The new rules limit flying below 18,000 feet within a 34.5-mile radius of the event sites. Passengers on commercial airlines will be required to remain seated for 30 minutes after takeoff and 30 minutes before landing in the three areas.

Private flight will be banned or in some cases limited to aircraft operating under instrument flight rules. Sightseeing and training flights will be prohibited.

In New York, the restrictions will be in effect from 7 a.m. EDT on Sept. 11 until 8 p.m. on September 13. Private planes will be banned shortly before, during and after public outdoor events on all three days.

In Washington, the restrictions will be in effect from 8:30 a.m. until 11 a.m. on Sept. 11. Flights will be banned over a ceremony at the Pentagon.

In Somerset County, Pa., flights will be banned over and near the outdoor ceremony on Sept. 11.