Belgian Defense Minister Theo Francken hit back at Dassault CEO Éric Trappier over the French executive’s refusal to let Belgium participate in a European next-generation fighter jet project.

“As a founding member of NATO and the EU, a loyal ally and host of the headquarters, we have no lessons to take from arrogant industrialists,” Francken said.

Earlier this week, Trappier said he did not want Belgium to join the program, known as the Future Combat Air System (FCAS), unless the Belgian government stopped purchasing American-made F-35s — one of the main rivals to Dassault’s Rafale jet.

FCAS is led by France’s Dassault, Airbus’ German unit and Spain’s Indra and is designed to deliver a next-generation fighter jet by 2040. However, it’s currently bogged down in disagreements around the work share, which Paris and Berlin are trying to solve. Dassault and Airbus have a notoriously fraught relationship, and the Rafale-maker wants to take the lead in making the FCAS’ warplane.

Belgium is an observer member, but said last week it had earmarked €300 million for the program and will ask to become a full member “as soon as possible.”

“If I was diplomatic, I would say that Belgium is welcome if they stop buying F-35s. If I wasn’t, I would say they’re really taking us for fools,” Trappier said this week.

Trappier and Belgium have a long history of sparring over the Belgian government’s decision to purchase F-35s instead of Rafales. In 2023, the Dassault CEO pushed back against Belgium’s bid to become an observer, leading to a public spat with Francken’s predecessor, Ludivine Dedonder.

“The government will assess its position in the FCAS project,” Francken said.