It was definitely RAF Little Rissington, actually occupied by the US forces as a storage base I believe, but limited use back then by the air cadets for gliding, stopped not much later.
Geographically may have been closer to Great Rissington of course, much like RAF Brize Norton is actually closer to Carterton (which in the days of crackly radio sounded too much like Cardington). Or are you thinking of RAF Upper Heyford, another US base?