Now let’s move to the gruesome. The worst sort of business is one that grows rapidly, requires
significant capital to engender the growth, and then earns little or no money. Think airlines. Here a
durable competitive advantage has proven elusive ever since the days of the Wright Brothers. Indeed, if a
farsighted capitalist had been present at Kitty Hawk, he would have done his successors a huge favor by
shooting Orville down.

The airline industry’s demand for capital ever since that first flight has been insatiable. Investors
have poured money into a bottomless pit, attracted by growth when they should have been repelled by it.
And I, to my shame, participated in this foolishness when I had Berkshire buy U.S. Air preferred stock in
1989. As the ink was drying on our check, the company went into a tailspin, and before long our preferred
dividend was no longer being paid. But we then got very lucky. In one of the recurrent, but always
misguided, bursts of optimism for airlines, we were actually able to sell our shares in 1998 for a hefty gain.
In the decade following our sale, the company went bankrupt. Twice.

http://blogs.wsj.com/moneybeat/2015/01/05/warren-buffetts-investing-blind-spot-airlines/