United Airlines announced Thursday it will immediately start hiring pilots, beginning with a group of 300, to be ready to meet growing demand for air travel.

"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, the airline's chief of flight operations, said in a memo to employees obtained by AFP. 

The first offers will go to pilots who had conditional job offers or were in line for jobs last year, he said.

However, "the number of new pilots needed will be dependent on our recovery from the COVID-19 pandemic," trying to assuage concerns of current pilots who have weathered the pandemic disruptions.

Airlines were forced to take drastic measures to cut costs since the start of the Covid-19 pandemic caused travel to come to a screeching halt, including encouraging tens of thousands of employees to retire or leave the company, or take unpaid leave.

Passenger airlines lost a total of $35 billion in 2020, according to the industry federation Airlines for America (A4A). 

But with the help of multiple rounds of government aid, air carriers have been preparing for a resumption of traffic. 

United has scheduled more flights in May to popular tourist destinations in Mexico, the Caribbean and Central America, than at the same time in 2019, before the pandemic. 

In another sign of a return to normal, Delta Air Lines announced on Wednesday that starting May 1 it would no longer block the middle seats as it had done since the start of the pandemic, in order to be able to offer capacity to travellers. 

Delta was the last major company in the United States to maintain this social-distancing measure on its planes. 

Mask mandates, however, remain in place for passengers.