Cyrano - interesting I was also doing a back of the envelope and we have come up with the same fare levels which are roughly equivalent to the first class rail fare, always a good guide!
EI-BUD - I am slightly confused where you get a daily average of 160 passengers? Flybe themselves quote just under 100.000 during 2012 which is nowhere even remotely close to that.
Bear in mind the subsidy to the airport this year is budgeted at £3 million and passenger throughput including London is down to 166,000 it doesn't take a market analyst to see how much extra each one has to contribute to make the airport break even!! Now take away the 100,000 on Gatwick and see the result....£45 per head.
I have a cheaper plan, want to come to Cornwall or go to London, here you are have a free rail ticket.