"We are a listed company. He is free to make (an offer) at any time. But non-Europeans cannot hold a majority stake in a European airline," said Michael O'Leary at a press conference in Dublin.

European rules require that an airline based in the European Union be majority-owned by EU citizens. Born in South Africa, Elon Musk also holds Canadian and American nationalities.

True to his direct and controversial style, he nevertheless invited the billionaire to invest in his airline, considering it "a very good investment, certainly more advantageous than the financial returns he obtains from X".

The tensions between the two come in the wake of Ryanair's leader's rejection last week of Elon Musk's Starlink satellite network to equip his fleet with Wi-Fi.

The basis of the decision was the cost of between 150 and 250 million dollars (128 to 213 million euros) per year, due to the aerodynamic drag caused by the antennas and the associated fuel surcharge.

In an interview with Irish radio Newstalk, O’Leary had also called the head of Tesla and SpaceX an "idiot" and his social network X a "cesspool".