U.S. Airways and UAL Corp's United Airlines are deep in merger discussions, the New York Times reported on Wednesday.
Such a deal would create one of the world's largest airlines.
Any such deal is not expected to be announced for at least several weeks and could fall apart, the newspaper reported, citing people briefed on the matter.
An alert posted on the newspaper's website said US Airways would be the acquirer, although an accompanying story made no such reference.
Shares of both airlines rose after hours, along with the shares of other airlines.
In February, executives at both airlines said they would be open to a merger, and that the airline industry needed consolidation to return to profitability.