Topjock
I think that the Ryanair Business plan also depends on selling new 737-800 and leasing them back.
The last full tax year showed an increase in the number of aircraft leased off balance sheet from 25 to 35. I presume that those aircraft are part of a sale and leaseback rather than a lease outside those on order.
One of the interesting aspects of the Ryanair accounts is the continual changing of accounting policy with regard to depreciation.