Forest flyer is right.
Hasn't Eastleigh has been owned by BAA for years indirectly, the previous operators were Airports UK which was a division of BAA?
Can't see why runway length is much of a factor when a fully-laden 757 or 320 can depart SOU to the canaries and south med? The 146-300 doesn't have a great power-weight ratio which hinder's that particular a/c's performance out of SOU. As a/c get newer and better strip length is less of a hinderance, take the E-195.
T