Warren Buffett is loading up on airlines (AAL, UAL, DAL, LUV)

Warren Buffett is loading up on airline stocks.
Buffett's Berkshire Hathaway is taking new stakes in American Airlines, United Continental, and Delta Air Lines, according to the company's latest 13-F filing.
The firm also took a stake in Southwest Airlines, according to CNBC.
Stocks for the firms jumped in after-hours trading. Around 4:19 p.m. ET they were at:
American Airlines: up 2.2% to $44.35 per share.
United Continental Holdings: up 1.0% to $63.58 per share.
Delta Air L