But would it benefit the new regime to unload its 737 fleet and start fresh with just Airbus and Embraer? Could they sell the existing boeing fleet when the new Airbus's roll in?
I can't say for sure about the West fleet, but the entire East fleet is either leased or mortgaged (EETC's to be more exact - the planes are collateral for loans).
The leased planes obviously can't be sold, only returned to the leasor as the leases expire or with agreement of the leasor. No money to buy new planes there.
The mortgaged planes could be sold, with some/all of the proceeds going to pay off the EETC's. I have no idea how much cash could be raised, if any.
I can only assume that the West fleet is much the same, since this is pretty much the pattern for all airlines. Sorta like houses - most people don't plunk down cash, they either rent or borrow.
Of course, all this doesn't preclude changing over the fleet over time. As leases expire, replacement planes are leased or financed with new EETC's. Likewise, as mortgaged planes are retired, replacements are leased or financed with new EETC's. Just hard to do in a short time. I would expect that over the next 5-7 years the 737's will be all but gone.
Jim
[Edit to add] US was pretty successful in BK1 at driving down the cost of aircraft leases. It was after 911 when used aircraft values were pretty much in the toilet and leasors didn't want the airplanes on their hands to remarket.