US airlines offered mixed quarterly results Thursday, raising concerns about the industry's recovery after being clobbered in recent months by the recession.
US Airways and JetBlue Airways surpassed estimates, with US Airways narrowing a fourth-quarter loss and JetBlue reporting a profit.
Alaska Air also swung to a profit, but it missed estimates and its shares fell.
"People are concerned about the economy and whether or not it's truly recovering," said Helane Becker, analyst with Jesup & Lamont.
Fuel costs are projected to rise and airlines will have to spend more to accommodate more traffic, Becker said. Meanwhile, the industry has been unable to lift fares in 2010, she said.
"How fast can revenue come back?" Becker said. "That's really the issue."
The Arca Airline Index fell 2.2 percent, outpacing a drop in the broader stock market. JetBlue shares fell more than 6 percent to USD$5.18, while Alaska Air's stock sank more than 8 percent to USD$33.23.
But US Airways shares jumped 6 percent to USD$5.15 in afternoon trading on the New York Stock Exchange.
"We see cash levels as adequate, and think (US Airways) has done a good job reducing cash outlays for 2010," Standard & Poor analyst Jim Corridore wrote.
The airline industry suffered in 2009 under the weight of the recession, which caused businesses to cut their travel budgets. Airline executives have expressed cautious optimism that business travelers are returning to the skies.