Quite an interesting chat with an industry contact recently. One of the big issues at Southampton is the cost of aviation fuel, which is surprising when it's that close to Fawley refinery! It's apparently the most expensive of any decent-sized airport in the country - not far off double that at Bournemouth apparently - and unless you can carry roundtrip fuel into SOU, which isn't easy with the fairly limited runway length, it's incredibly costly to pick up fuel there. Might this be one reason behind the airport's stagnation?