AIRBUS SE United CEO Scott Kirby recently visited Toulouse to sound out the manufacturer about a possible deal after a mid-air emergency on an Alaska Airlines 737 MAX 9 raised fresh doubts about the MAX 10's certification, the sources said.
"United Airlines is in talks with Airbus about possible alternatives to ordering the MAX 10. To my knowledge, no agreement has been reached," said a person familiar with the discussions.
The discussions are at an early stage and there is no guarantee of an agreement, the sources said.
Airbus and United Airlines declined to comment.
Scott Kirby's previously unreported trip to Toulouse is the latest twist in a crisis involving Boeing, as the manufacturer seeks to reassure the public and regulators about the quality and safety of its production, while preventing key orders from slipping through its fingers.
Last week, Scott Kirby described the partial grounding of the MAX 9 as "the last straw" in the wake of certification delays for the MAX 10, the largest aircraft in a category whose reputation has been tarnished by two fatal accidents.
United has not cancelled any of its 277 MAX 10s on order, but has removed them from its internal plans, Scott Kirby told reporters.
Bloomberg News reported on Friday that Airbus was looking to buy A321neo positions on the market in order to be in a position to formulate a proposal in the event of an opening. Trade publication Air Insight reported that Airbus and United were in talks.
Signs of a potential deal with Airbus have raised "concerns" at Boeing, said a senior industry source. The manufacturer is currently unable to provide the clarity that United and others want on the MAX 10 due to doubts over its certification timetable.
Boeing, which has pledged to address quality issues that may have caused a door plug to explode on a MAX 9 and led to the plane's partial grounding, declined to comment on commercial discussions.
Boeing Commercial Airplanes CEO Stan Deal said in a letter to staff on Friday that he was "deeply sorry for the significant disruption and frustration to our customers".
These discussions come as Airbus controls the busiest part of the jet market, where its 240-seat A321neo has a strong lead over the forthcoming MAX 10.
By contrast, Airbus has failed to deliver a single one of its largest A350 jets to United after winning a sale back in 2010, following a merger between United and Boeing's long-standing customer Continental Airlines that triggered a review.
Orders have been progressively postponed until around 2030.
According to industry sources, the two sides have tentatively agreed that any deal for A321neo aircraft should revisit the 45 A350s ordered by United, and include at least a firmer delivery schedule after several postponements by the Chicago-based airline. (Reporting by Tim Hepher and Rajesh Kumar Singh, with Valerie Insinna, written by Jane Merriman, version française Benjamin Mallet)
