Over 30,000 airline workers were furloughed last week and were holding out hope that they would get called back to work if lawmakers reached an agreement.
Aviation industry leaders had been asking for a $25 billion "clean extension" of the Payroll Support Program that would prevent involuntary layoffs until March 2021.
House Speaker Nancy Pelosi, D-Calif., who signaled Friday that the House could potentially pass a standalone bill to extend the PSP for airline workers, said by walking away from coronavirus relief talks Trump is showing "his contempt for science, his disdain for our heroes -- in health care, first responders, sanitation, transportation, food workers, teachers and others."
American Airlines said it was "disheartened" to hear negotiations had halted.
"The past week has dealt a crushing blow to the American Airlines team and the aviation industry, and we were hopeful that overwhelming bipartisan support for the Payroll Support Program would result in immediate action to protect jobs and service to communities across the country," the carrier said in a statement.
Sara Nelson, president of the Association of Flight Attendants-CWA, which represents flight attendants from multiple U.S. airlines, said her union will begin emergency meetings "to determine our options to protect people and keep them from harm."
"We need rational people to take control and help our nation," Nelson said in a statement.
ABC News' Ben Gittleson, Mariam Khan and Sam Sweeney contributed to this report.