Interest on £6,000 - £15,000
...
you would have to wonder if these people did maths at school or just like wasting money.
I'm wondering
also assuming 30 hours/year really skews the figures - you're dominated by the fixed costs. A "typical PPL" doesn't own an aeroplane, so trying again with 100 hours/year makes it look much better at around £35-£40/hr incl (reasonable!) interest...