N3075E is taken. It's currently assigned to a Reiland Robert R RANS S-12 registered in Morgan City, LA.
See the full aircraft record →A tail number only frees up if the owner deregisters the aircraft or moves it to a different N-number — and even then the FAA holds it before releasing it to the public.
N3075E has been worn before. Past registrations from FAA deregistration records:
Tails one nudge away from N3075E that aren't assigned or reserved: