TS appears very ill-informed. The Basic Airborne course is not
exclusive to any formation but Commandos, SOF and Naval divers
(regardless of NSF or regulars) have priority. The advance module
i.e. combat jump is more or less exclusive to these groups.
Lower down on the priority scale are the regular servicemen and
then they have some slots for the NCC as some sort of PR. NSFs
(other than the 3 vocations mentioned) have an extremely low chance
of going for it.