A ground crew prepares to unload luggage from an arriving Delta Airlines flight at the Seattle-Tacoma International Airport on March 15, 2020 in Seattle, Washington.

President Donald Trump said Monday he plans to back the airline industry "100%" as it's been roiled by the coronavirus pandemic.

"We're going to back the airlines 100% − it's not their fault," he said.

"We'll be backstopping the airlines and helping them very much," he later added.

Airline shares came off their lows on Trump's remarks, though most of them closed at fresh multi-year lows. Delta, United and Southwest closed down 6.6%, 14.8% and 9.1%

American Airlines, which was higher before Trump's comments, closed at the highs of the day amid the press conference, up 9%. It has the most debt of its peers.

U.S. airlines are seeking government assistance of more than $50 billion, including a mix of direct aid and loan guarantees, as the industry reels from the coronavirus outbreak.

Airlines for America, which represents carriers including Delta, United, American and Southwest, have recommended passenger carriers immediately receive up to $25 billion in grants to compensate for reduced liquidity and in the medium term $25 billion in low- or zero-interest loans.

Trump did not confirm the size and structure of the aid the administration plans on offering the industry but did say he has communicated with the airlines his plans to help them.

"We've told the airlines we are going to be helping them," Trump said.

Trump's words of support for the airline industry come as Congress is already discussing the third package to help ailing companies, states and individuals stricken by the virus. A second package was passed by the House this weekend but has yet to go through Senate.

The next package may be monumental in size. Senate Minority Leader Chuck Schumer is planning his own aid proposal of at least $750 billion. It would money to help individuals and small businesses, including forbearance on federal loans, a moratorium on evictions and foreclosures, assistance for small businesses and emergency child care.

The next package may also be politically thorny in an election year, particularly as the pain becomes so widespread. The airline industry has argued, though, the challenges they are facing are not self-inflicted, unlike that which the banks faced in 2008.

"It's not their fault − it's nobody's fault unless you go to the original source. But it's nobody's fault, and we're going to be in a position to help the airlines very much," said Trump.

CNBC's Leslie Josephs and Tom Franck contributed to this report