21.   A slim hope lies in getting commandos on board the commercial jet.

22.   Administration aides suggested that the president himself was in danger Tuesday when terrorists hijacked four commercial jets and began flying them into landmark U.S. buildings.

23.   Airbus faces a tougher struggle in its goal of seizing half the commercial jet market.

24.   All three trained to fly commercial jets.

25.   But some aviation experts said that as long as propeller aircraft and commercial jets share runways, such collisions are almost inevitable.

26.   But what happens to competition in the commercial jet and defense businesses with McDonnell Douglas out of the way?

27.   But, as he did with his earlier studies, Atta remained focused, eventually gaining all the training he would need to fly a commercial jet.

28.   Catic was a partner with McDonnell Douglas in what was known as the Trunkliner program to build McDonnell Douglas commercial jets in China.

29.   Chances of a mechanical ignition were slim because every electrical system on commercial jets is designed to minimize the chance of a significant spark.

30.   Carriers have seen their revenues plunge as passengers avoided flying after terrorists crashed commercial jets into the World Trade Center and the Pentagon.