I believe the regulation is that there is no requirement on 19 seats or fewer. The problem is that if you wish to deposit passengers at a screened area at the destination, they must be screened to an equal level. So AA would probably need to use a portacabin at Exeter rather than the main terminal unless full security were to be in place at Swansea. The same arrangement is in place at Islay ('terminal 2') for Hebridean Air Services' flights to Colonsay and Oban. Mssrs Brem-Wilson, who run AA, tend to deride this sort of thing as 'bureaucracy', so maybe they intend to surmount it.