Reeling from the coronavirus crisis, U.S. airlines are seeking over $50 billion in financial assistance from the government, more than three times the size of the industry’s bailout after the Sept. 11 attacks.

The exact form of the aid—and the amount—is under discussion with Trump administration officials and congressional leaders. A potential aid package could include government-backed loans, cash grants and other measures including relief from taxes and fees, according to an airline trade group and others familiar with the discussions.

“We’re going to back the airlines 100%,” President Trump said at a news conference Monday. “We have to back the airlines. It’s not their fault.”

Industry trade group Airlines for America, or A4A, also proposed $8 billion in grants and guarantees for cargo carriers. U.S. airports are separately seeking $10 billion in assistance to counter forecast full-year losses already approaching $9 billion, according to a person familiar with the request.

Airlines are facing an existential crisis, with United Airlines Holdings Inc. alone estimating its revenue would be down $1.5 billion in March from a year ago and would post a first-quarter loss. A4A said all seven of the carriers it represents could run out of money in the second half of the year or sooner.