They buy new planes all the time though; Airbus is selling its planes as fast as it can build them. And airlines are constantly trying to get newer planes beca

They buy new planes all the time though; Airbus is selling its planes as fast as it can build them. And airlines are constantly trying to get newer planes because they're more fuel-efficient, and the capital cost of the plane itself isn't that big a deal compared to how much money they'll spend on fuel while it's in service.