I worked at the AA from 78-79 as a Radio Tech at HQ Fanum House & also lived in Basingstoke from 71-85. As a department we did radios in all vehicles including the DGs Daimler & all the management cars, which were Rover SD1s & a few Princesses.
I wasn't aware of any aircraft they flew and certainly nothing near Basingstoke.
I believe there was a DH Rapide in the early days which would have been pre- Fanum House in Basingstoke when the AA had an HQ in London. Just checked the Rapide was 57 the year of my birth.
This forum won't let me post URLs which is a bit dim. If you google AA & go to their website & then timeline you'll find the info.