As airline fleets age and airlines operate under bankruptcy court protection, that figure is likely to edge up.

At the turn of the 21st century, the 727 was still in service with a few airline fleets.

In 2002 the airline fleet was as follows:

"While the shutdown was immediate, the start-up is going to be slow" because airline fleets are widely scattered, she said.

Maintaining higher fares could prove difficult as rising deliveries of new planes swell airline fleets later this decade.

In their subsequent coverage, the media focused heavily on the fact that TWA's airline fleet was among the oldest in service.

The nation's airline fleet is aging beyond the years of service that manufacturers originally anticipated.

As of March 2007 the airline fleet includes :

The three types of planes make up 50 percent of the airline fleet in the United States.

That will be the first airline fleet to be completely equipped with this system.