During COVID, airlines flew empty planes back and forth at a loss just to keep the right to their established routes and air ports.

What nonsense. I certainly feel like a medieval peasant sitting in a high speed train crossing a large country while I read a book for a few hours, costing three hours of work at the median salary if you book your ticket far enough ahead. (They also allegedly run on wind energy, but of course that's creative accounting and another industry is simply attributed the corresponding amount of coal/gas electricity.) Traveling is accessible, fast, and comfortable. The main expense is the hotel(s)