The company is also seeing a surge in demand for trans-Atlantic flights after the White House's decision late last month to reopen the country to fully vaccinated travelers from around the world.

Trans-Atlantic flights accounted for 11% to 17% of 2019 passenger revenues for the big three air carriers - American Airlines, United Airlines and Delta.

Bastian said Delta's staff vaccination rate had risen to 84%, driven in part by the company's decision to impose a $200 monthly health insurance surcharge for those who had not been vaccinated. He said he expects the rate to surpass 90% by Nov. 1.

Delta, however, is the only major U.S. airline that has still not mandated coronavirus vaccines for employees despite the pressure from the White House.

Bastian said the company has not decided whether to mandate COVID-19 vaccines.

"We're obviously studying it," he said, referring to President Joe Biden's executive order (EO) requiring federal contractors to mandate vaccinations.

"I'm not sure how far you need to go in order to be in compliance with the EO," the CEO said.

The White House is pressing major U.S. airlines https://www.reuters.com/business/aerospace-defense/exclusive-white-house-pressing-us-airlines-quickly-mandate-vaccines-2021-10-01 to mandate COVID-19 vaccines for employees by Dec. 8 - the deadline for federal contractors. Large U.S. airlines have a number of federal contracts.

(Reporting by Rajesh Kumar Singh; Editing by Himani Sarkar and Bill Berkrot)

By Rajesh Kumar Singh