But you might find it difficult to set up a new account until you have suitable personal identification in your new destination (such as a job or rental contract or social security number in the US), so make sure you have a decent credit card with zero foreign transaction fees to get you through the first few weeks.
They can lose revenue when they switch passengers to other carriers, but this is a zero sum industry game, and they also take in fees from other airlines to carry their passengers.
The only beneficiary of accelerated mortgage payments is the bank, whose money you are effectively lending back to it at zero percent interest, money it can hold to bolster its capital requirements or lend to someone else and earn fees by selling the mortgage to a third party.