To keep your pilots alive for ever, make a copy of the 
PILOTS.DAT file before going on a dangerous mission. 
If you get killed, you can copy the file back and your 
pilot is resurrected as though he had never flown the fatal 
mission. For example, to copy the file, change to the Aces 
directory and type:

   COPY PILOTS.DAT BACKUP.XXX

To resurrect a pilot, change to the Aces directory and type:

   COPY BACKUP.XXX PILOTS.DAT

Make sure you copy the PILOTS.DAT file every time you 
successfully complete a mission.