Airlines are wonderful generators of profit—for everyone except themselves. Even in good times their margins are as thin as a boarding pass, and in recent years they have more often lost money. Averaged over the past four decades, the net profit margin of the world's airlines, taken together, has been a measly 0.1%. By contrast, other bits of the travel business that depend on the airlines—such as aircraft-makers, travel agents, airports, caterers and maintenance firms—have done very nicely.
Among these are the giant computer companies that do reservations for airlines, who receive almost double the airlines' net profits in fees every year.