If you’re thinking Aunt Bee (Frances Bavier) is still alive, I’m sorry to tell you that she left this earthly realm in 1989.
http://en.wikipedia.org/wiki/Frances_Bavier
You are correct that Ron Howard (Opie) and Jim Nabors (Gomer) are still alive. George Lindsey, who played Goober Pyle after Gomer went off to the USMC, was the other recently-deceased cast member of the show.
I coulda sworn she was the pilot of a plane I was on the other day.