A spat over in-flight Wi-Fi has spiralled into a public verbal brawl between Elon Musk and Ryanair CEO Michael O’Leary, pitting one of the world’s richest men against Europe’s most outspoken airline boss.

The clash burst into the open after O’Leary dismissed Musk and his satellite internet business in a radio interview on Ireland’s Newstalk. Responding to Musk calling him “misinformed” over Ryanair’s refusal to install Starlink Wi-Fi, O’Leary told listeners he would “pay no attention whatsoever to Elon Musk.”

“He’s an idiot — very wealthy, but still an idiot,” O’Leary said. He also described Musk’s social media platform X as a “cesspit.”

Musk fired back on X, writing: “Ryanair CEO is an utter idiot. Fire him.” In a follow-up post, he accused O’Leary of getting Starlink’s fuel-burn impact wrong “by a factor of 10” and added: “Fire this imbecile.”

Ryanair’s official X account also joined the fray, mocking Musk during a reported outage on his platform, replying: “perhaps you need Wi-Fi @elonmusk?”

Behind the insults lies a substantive dispute about costs and aircraft performance. Ryanair has publicly ruled out installing Starlink across its more than 600 Boeing 737s, arguing the external antennas would increase drag and fuel consumption.

O’Leary has said the technology would impose around a 2 percent fuel penalty and could cost the airline hundreds of millions of dollars a year, a trade-off he says makes little sense on short-haul flights where passengers are unlikely to pay for connectivity.

Musk disputes those figures, pointing to airlines already flying with Starlink-equipped aircraft and arguing that fast internet will increasingly shape passenger choice.