AT: "ar" An Air Defense Team was a specialized group of Starfleet personel, which were at hand in on an alternate reality Earth to deal with airborn attacks.
In 2259, when John Harrison began his attack at the Daystrom Conference Room at Starfleet Command, admiral Christopher Pike requested such a team to assist. (Star Trek Into Darkness)
It was not explicitly said if these were part of Starfleet, though is assumed here because is Starfleet usually responsible for the defense of their own instalations.