A/C does not show as flyable

Hi,
I have number of AI aircraft, most show as flyable when selecting aircraft for flying. As I fly only approx 5 aircraft, I would like to delete many from the flyable selection. One instruction suggests that the Aircraft Type should be changed from 2 to 0, also that AITM should be altered? I did not find any of this in the amendable 'aircraft' files and the air files show only signs and symbols? Could you please adv which file/terminology to change to delete AI aircraft from the flyable menu.
MANY thanks,
Peter

Hi,
Actually have found out about AirEd, which I have downloaded and changing Aircraft Types from 0 to 2 in air files does the trick.
P.