After a rough 2020, the airline industry is signaling clear skies ahead going into the spring and summer travel season.

On Monday, industry execs were making the rounds at a J.P. Morgan investment conference, and the message was by and large upbeat. Delta Air Lines (DAL 1.25%) CEO Ed Bastian warned that while the airline was likely to post a "large loss" in the current quarter, bookings have picked up in the last five weeks as the vaccine rollout gained momentum.

March revenue is coming in about 40% higher than February, and the month is "at or pretty darn close to breakeven" in terms of cash burn, Bastian said.

Airplanes parked at an airport.

Image source: Getty Images.

The tone was similar from others. United Airlines Holdings (UAL -0.06%) CEO Scott Kirby said his company expects to halt cash burn in March and continue the positive trend. And American Airlines Group (AAL 0.14%) said it has seen "a real uptick" in bookings, with the last three weeks the best for ticket sales since the pandemic began.

The data from the Transportation Security Administration also suggests a rebound in travel demand. The TSA screened more than 1 million passengers on Sunday, the fourth consecutive day when screenings exceeded 1 million. That hasn't happened since mid-March 2020, before the pandemic fully took hold in the United States.

Though the airlines are on the mend, a full recovery is still expected to take time. Most of the initial demand surge is expected to be leisure travel, and not more-lucrative business travel. Given the uneven vaccination rates around the globe, international traffic is also likely to lag.

The airlines also took on billions in new debt during the pandemic, and will need time to repair their balance sheets before focusing on post-downturn expansion.