Wouldn't it be great if you could get investors from other airlines? And when the competitor airline owns a majority, you become a subsidiary of the airline. Of course, players should be allowed if they want their airline to be publicly traded or private. Players would also decide how many of their shares they want to sell to the public which would, in turn, control the price per share.
Another idea is that other airlines can offer loans and straight up money, to airlines requesting it. And that they together could set interest rates term length and if the airline has enough money they could pay it off at once.
This is just something I think would be fun and interesting to use in the new version. Any suggestions? Improvements? Different ways such a system could work? Or anything else, please comment! I am eager to hear what other people think.