Southwest Airlines Co said it expects a key revenue measure to rise in the low-single-digit percentage range for both the month of February and the first quarter.

Chief Financial Officer Tammy Romo gave the forecast at a JPMorgan aviation conference that was carried on the Internet. Despite concerns that the effects of automatic U.S. spending, cuts known as sequestration, would hurt demand, Romo said March bookings look "solid" for Southwest.

Meanwhile, Delta Air Lines Inc said in a statement on Monday that its unit revenue, which is also known as passenger revenue per available seat mile, rose 5 percent for the month of February, aided by business revenue gains, fuller planes and better performance on European routes.