"Our highest financial priorities right now are restoring our balance sheet and investing in our employees and customers," United Airlines said in an emailed statement.
The carrier plans to take delivery of nearly 300 new aircraft over the next several years.
As air travel roars back, airlines are also prioritizing on debt reduction following a borrowing binge during the pandemic.
The big three national carriers - American Airlines, United and Delta Air Lines - had a combined $85 billion in net long-term debt at the end of the second quarter.
Cost pressures due to a shortage of workers and mounting economic worries have also sparked investor concerns on carriers' ability to repair balance sheets, likely limiting room for capital returns.
"Delta's top financial priority is restoring its financial foundation by generating sustained and meaningful profitability and cash flow to support debt reduction and reinvestment in the business," the airline said.
American Airlines pointed to chief financial officer Derek Kerr's interview in August to The Associated Press, when he said the carrier had no plans to do any share repurchases and all of its excess liquidity would be used to pay off debt.
As part of the federal COVID-19 relief package, airlines had been prohibited from buying back their shares. The ban had expired on Sept. 30.
Airline unions, representing hundreds of thousands of workers, had launched a public campaign against stock buybacks in August. Some U.S. lawmakers are also pressing airlines not to resume stock buybacks.
Delta, American and United Airlines are schedule to report earnings in the next few weeks.
(Reporting by Priyamvada C and Abhijith Ganapavaram in Bengaluru; Editing by Krishna Chandra Eluri)