The story

United Airlines approached Delta Air Lines last year about a potential merger that would have combined two of the largest U.S. carriers, according to The Wall Street Journal. United CEO Scott Kirby contacted Delta CEO Ed Bastian to pitch the potential tie-up. Delta's leadership discussed the proposal and evaluated the potential benefits as part of preliminary due diligence, but the talks did not progress and both airlines moved on.

The proposed merger would have had sweeping implications for the airline industry and likely faced scrutiny from federal antitrust regulators and state attorneys general, according to The Wall Street Journal. Kirby also reportedly explored a possible merger with American Airlines earlier this year, but American rejected the proposal and CEO Robert Isom criticized the idea as anticompetitive.

Last month, Kirby told Reuters that consolidation is unlikely for United, though the airline remains open to buying airport slots, gates and other assets. A United spokesperson said the airline had nothing to share, and Delta declined to comment on the reported talks.