Delta Air Lines Inc. signaled the worst of the coronavirus pandemic is likely behind it, as the airline anticipates that travel demand will continue to gain steam in the coming months.

Delta’s brighter outlook came as it reported a net loss of $1.2 billion for the first quarter on Thursday—its fifth straight quarter of losses—but said its operation began generating cash again last month for the first time in a year, and passenger revenue that month jumped 50% from February.

The beginning of the year, when Covid-19 cases and fatalities were surging, looked bleak for airlines. But as more people have started receiving Covid-19 vaccinations, interest in travel has returned. Delta said that its net sales—the difference between new ticket sales and refunds—doubled from January to March.

Airlines are hoping that travel will roar back to life this summer, and the recent rise in bookings is the latest sign that the rebound they have long been hoping for might materialize. With domestic leisure bookings at 85% of pre-pandemic levels, Delta says it is on track to potentially turn a profit this summer.

“It’s clear that our business is turning the corner. We’re into an active recovery mode,” Chief Executive Ed Bastian said.