United Airlines, anticipating a recovery in the travel sector as summer approaches, has told staff it has begun the process of hiring more pilots, according to an internal email reviewed by CNBC.

The carrier is the first large U.S. airline to restart the hiring of pilots, one of the biggest indicators yet that the airlines believe the worst of the coronavirus pandemic is over.

And its worst was devastating.

United and virtually every airline in the world lost billions in the last year – $35 billion alone just for U.S. airlines – and cut flights, parked planes and put employees on furlough or asked them to take buyouts or early retirement to cut costs and stem the tide of losses.

Three rounds of government aid through stimulus packages helped, as the airlines received a collective $54 billion in grants and loans.

CNBC noted that United will start by hiring 300 pilots who had conditional job offers or training scheduled last year before the airline called off hiring.

Between vaccinations that began in December of 2020 as well as a pent-up demand for travel , the airlines are finally seeing things turn around.

“With vaccination rates increasing and travel demand trending upwards, I’m excited to share that United will resume the pilot hiring process that was halted last year,” Bryan Quigley, United’s senior vice president of flight operations, wrote in a staff note on Thursday, which was viewed by CNBC. “We’ll start with the approximately 300 pilots who either had a new hire class date that was canceled, or who had a 2020 conditional job offer.”