Arizona2, let me move this to our Avis Rental Car forum for best advice. Ocn Vw 1K, Moderator, TravelBuzz.

(In my rental experience, one can return to an airport location if one arranges this with the rental car company, either at reservation, at pickup or while on the road) . Otherwise, return to an airport location (if it wasn't the pick-up location), could cause the rental to be re-priced, resulting in a cost increase to you.)