I downloaded a replacment air file for the default Learjet 45, but the new file is very bad (when you have the autopilot on and go into a turn, the plane does not stay at altitude. It dropped from 32,000 feet to 14,000 feet) When I replaced the old air file I forgot to back up the original. Is there a way to get the original air file back from the FS2002 discs? If so how?

The Lear 45's airfile is on Disk 1. Put Disk 1 in the drive, right click on the D: drive icon and select "OPEN" from the drop down menu. Locate the CAB file named AIRCRAFT, open it with WinZip Classic, and scroll down to the Lear 45 files. You will find the Lear45.air among them.

thanks! All fixed now.