March 17, 2021: According to a company memo sent on Tuesday, JetBlue Airways told flight attendants who had taken leaves this spring that they would be called back to work early to handle rising travel demand.

The move came after several airline CEOs, which include JetBlue’s, reported that bookings are on the rise that will extend till this summer. The trend is a sign the industry is beginning to recover after losing $35 billion the previous year. Their optimism sent airlines’ stock prices to higher levels in over a year.

“As we enter a new phase of the pandemic with cases decreasing and vaccination rates increasing, our focus is now getting ready to ramp up our operations for a busy summer season safely, and our Inflight Crewmembers are critical to our recovery opportunity,” said a company memo to flight attendants.

The New York-based airline told flight attendants who took a two-month leave of absence scheduled for April and May to report back a month early and attend federally-mandated training on April 22.

“We’ve seen a significant increase in people booking in the last few weeks, March and into the spring and summer,” JetBlue’s CEO Robin Hayes said in an interview with CNBC on Monday.

Airlines spent most of 2020 encouraging employees to take buyouts or leaves of absence to lower their labor costs when demand plunged.

But carriers have grown more optimistic as a recovery takes shape. Spirit Airlines, for example, is starting to hire pilots and flight attendants again this month.

United Airlines had planned to cut as many as 14,000 jobs if Congress didn’t extend the latest round of government support.

The carrier’s CEO Scott Kirby told CNBC on Tuesday: “As long as there is not a setback, we are on the road to recovery, and we can put those days of talking about cash burn, layoffs, and things like that; largely in the 99rear-view mirror.”