If airports owning airlines and vice versa was a good business model Ryanair (with €4.3bn cash in the bank), EZY, BA, etc. would have been buying airports years ago.
Ahem ... TBI (that owned Flightline) also owned CWL and Scavsta airports, amongst others, guess where Flightline opted to fuel stop en-route to/from LED one trip and why one of their 146's was registered G-?TBI?.
Brymon owned/operated PLH & NQY airports, the owners of Air UK (B & C Shipping) also owned Servisair (so guess who did all of their handling) as well as an airport or few, anything in AMS is pretty much owned by KLM and so the list goes on!