Step 1: Work about five years, establish a track record of success at what you do, then apply to do your MBA at a top-ranked US Business School.
Step 2A: After that, work your way up through an industry (doesn't have to be an airline), preferably to a CEO position in a Fortune 100 firm. If you don't get to be a CEO, shoot for CFO at least. Your preferred route of advancement would be through finance.
Step 2B: Build a reputation as a strategic thinker with the ability to lead a firm through ups and downs. Make yourself known as a person who is firmly grounded in reality and who is capable of leading a large corporation through sustained growth without squandering its resources. Be ethical, be firm, but yet be compassionate.
Step 2C: While you are working your way up, learn everything you can about handling a huge company with plenty of fixed (and rapidly depreciating) assets, high fixed costs, (usually) plenty of debt, low margins, tough unions, and government and safety regulations. You should also gain experience in being answerable to shareholders, board of directors, government bodies, regulatory bodies, safety agencies, staff, unions, customers, the general public, the media, contractors, suppliers, alliance partners, strategic partners, subsidiary companies, creditors, debtors, banks, and industry analysts.
Step 2D: Network, network, network. Get to know the board of directors, major shareholders, and key decision makers at all the major airlines and other companies associated with those airlines. Play golf with them. Invite them for weekends at your home in the Hamptons. Bring them on yachting trips.
Step 3: Discreetly contact headhunters that specialize in the airline industry and sell them your credentials as a potential airline CEO once you have gained all this experience, skills and knowledge outlined above.
Step 4: Don't forget to have fun along the way.