The CAA statistics only relate to Air Transport movements and I assume do not include the Biz Jet Factor. The actual runway movement rate at Luton for June was in fact 11,242. This is far higher than the 7,253 movements that the CAA figures show.
I know London City have Biz Jets as well but they've got some distance to go yet.
Luton is the fifth busiest aiport in the country
