Scott Kirby, chief executive of United Airlines (UA, Chicago O'Hare), has floated the possibility of a business combination with American Airlines (AA, Dallas/Fort Worth), Bloomberg reported citing people familiar with the discussions.

Approached on the matter, United Airlines declined to comment, while American Airlines was not immediately available.

According to Bloomberg, Kirby pitched the idea to senior government officials, though it remains unclear whether a formal process to explore the deal is underway.

The report came days after the US transportation secretary, Sean Duffy, said he believed there is room for consolidation in the US airline industry and that while he would not pre-commit to anything, President Donald Trump “loves to see big deals happen.” Duffy said that any potential merger would have to be assessed on a case-by-case basis and that for any combination of larger airlines, “they’re going to have to peel off some of their assets.”

The current Trump administration has already approved the acquisition of Sun Country Airlines by Allegiant Air.

A combined United-American entity would be a massive global behemoth, unmatched by any carrier worldwide. ch-aviation data shows American Airlines operates an in-house fleet of 1,025 aircraft and fully owns three regional carriers (Envoy Air, Piedmont Airlines, and PSA Airlines). United’s fleet totals 1,097 aircraft, and it maintains partnerships with several smaller carriers without fully owning any, although that could change in the near term.

Any potential merger would have to be reviewed by antitrust authorities in the United States, and particular focus would be on their shared bases, such as at Chicago O'Hare and Los Angeles International. In Chicago, between the two carriers, they hold 82% of the weekly capacity, while in Los Angeles they hold 34.4%, ch-aviation schedules data shows.