07:13 AM EDT, 06/25/2025 (MT Newswires) -- Spirit Airlines on Tuesday urged the US Department of Transportation to block the proposed Blue Sky partnership between JetBlue Airways ( JBLU ) and United Airlines (UAL), arguing the deal is anticompetitive and would encourage further consolidation, multiple media outlets reported Tuesday.

The agreement would allow customers to book flights on both airlines' websites and use loyalty points interchangeably, the report said.

Spirit argued that the arrangement would turn JetBlue ( JBLU ) into a "de facto vassal of United" and reduce low-fare competition, Reuters reported. "This anti-competitive tie-up involving a dominant legacy carrier will neutralize the competitive benefit of an existing low-fare competitor," said Spirit, as reported by Reuters.

JetBlue ( JBLU ) said Spirit's claims misrepresent the partnership and argued that the partnership "does not include schedule coordination or revenue sharing." JetBlue ( JBLU ) said the parties "will remain competitors as they each will continue to publish, price, and market flights independently under their own brand and flight numbers," Reuters reported

Spirit also argued that approving the Blue Sky partnership would likely encourage American Airlines ( AAL ) and Delta Air Lines ( DAL ) to pursue similar deals, putting pressure on smaller carriers to follow suit, resulting in an "even more highly concentrated industry."

United referred MT Newswires to JetBlue ( JBLU ) for a comment.

Spirit, JetBlue ( JBLU ), American Airlines ( AAL ), and Delta Air Lines ( DAL ) did not immediately respond to requests for comment from MT Newswires.