United Airlines CEO Oscar Munoz is telling top lawmakers that the economic impact of the coronavirus pandemic on his industry is "much worse" than that experienced from the 9/11 terrorist attacks.

"We unequivocally support prudent steps like these to keep the American people safe. But, these actions have also created a fast-moving, financial crisis unlike anything the U.S. airline industry has faced before," Munoz wrote in a letter first obtained by Politico.

"In fact, the financial impact of this crisis on our industry is much worse than the stark downturn that we saw in the aftermath of the 9/11 attacks," he continued.

ADVERTISEMENT

United's top executive also noted that March is normally the airline's busiest month, but the company has so far flown 1 million fewer customers than usual. Munoz added that revenue projections for this month are $1.5 billion below March 2019 due to the significant drop in customers.

Many airlines like United have slashed their number of flights and restricted air travel in general, as the spread of the virus has continued worldwide.

"On behalf of the nearly 100,000 airline professionals at United Airlines, we -- the leaders of the company’s management and organized labor unions -- have a simple message: please act quickly – this week – to protect our livelihoods," Munoz said in the letter.

It was sent to Treasury Secretary Steven Mnuchin Steven Terner MnuchinLawmakers fear voter backlash over failure to reach COVID-19 relief deal United Airlines, unions call for six-month extension of government aid House Democrats plan to unveil bill next week to avert shutdown MORE, Speaker Nancy Pelosi Nancy PelosiPelosi: Ginsburg successor must uphold commitment to 'equality, opportunity and justice for all' Bipartisan praise pours in after Ginsburg's death Pelosi orders Capitol flags at half-staff to honor Ginsburg MORE (D-Calif.), House Minority Leader Kevin McCarthy Kevin Owen McCarthyTrump asked Chamber of Commerce to reconsider Democratic endorsements: report The Hill's Morning Report - Sponsored by The Air Line Pilots Association - White House moves closer to Pelosi on virus relief bill Trump's sharp words put CDC director on hot seat MORE (R-Calif.), Senate Majority Leader Mitch McConnell Addison (Mitch) Mitchell McConnellObama calls on Senate not to fill Ginsburg's vacancy until after election Planned Parenthood: 'The fate of our rights' depends on Ginsburg replacement Progressive group to spend M in ad campaign on Supreme Court vacancy MORE (R-Ky.) and Senate Minority Leader Charles Schumer Chuck SchumerPelosi orders Capitol flags at half-staff to honor Ginsburg Ginsburg in statement before her death said she wished not to be replaced until next president is sworn in Democrats call for NRA Foundation to be prohibited from receiving donations from federal employees MORE (D-N.Y.).

On Tuesday, Mnuchin met with Senate GOP members to discuss the details on the Trump administration's third legislative aid package aimed at combating the economic fallout from the virus.