big lease payments small maintenance cost. Fuel cost in five years? Lease payment in five years is known. How much does it cost if you can't meet the contract because you are not reliable? How many contracts can you maintain with reliability? Can you maintain a utilization rate of over 12 hours per day with old aircraft? Probably, but with a steep maintenance cost. How about RVSM, stage 4 noise compliance, and RNP approaches into less that desirable airports. You get all of that with new aircraft.