from FAQ:
Q: What do I have to do to restore a lost plane from the main planeset?
A: Make 10 successful battle sorties. Then the plane will be returned to the squad if there are planes of this type still left at storages. Attention: any battle sorties flown by any pilot of the squad count – including those made before the plane loss. So if you have 10 “unused” battle sorties, the plane might be restored almost immediately.
TIP: Supply missions also count, just make sure they’re over 15 minutes long to fit the “battle sorties” criteria.
I got the feel, that we never take our La5 back, from a lot of missions (plus than 10 for sure), maybe some bug ?????