Curiously, Ryanair is nearly alone in NOT using P2F cadets in the low-cost sector, while Vueling does and so do easyJet. It surprises me, too, but it's the truth.
How is Ryanair not using P2F cadets? Pay for a CV, pay for a TR, pay for medical, uniform, then get paid per block hour, no allowances, no expenses covered, no insurances. Walks like a duck to me...