United reportedly approached Delta Air Lines about a potential merger

United Airlines reportedly approached Delta Air Lines last year about a potential merger that would have combined two of the largest U.S. carriers . United CEO Scott Kirby contacted Delta CEO Ed Bastian to pitch the potential tie-up, The Wall Street Journal reported Sunday, citing people familiar with the matter. According to the outlet, leadership at the Delta discussed the proposal and evaluated the potential benefits as part of "preliminary due diligence," but the talks did not advance, and both airlines ultimately moved on.

A United spokesperson told FOX Business the airline had "nothing to share." Delta declined to comment.

A merger between United and Delta 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.

The previously unreported talks come as United works to expand its global reach. Kirby also reportedly explored a possible merger with American Airlines earlier this year. However, American rejected the proposal, and CEO Robert Isom criticized the idea as "anticompetitive," the WSJ reported.