You’re not going to believe this, but Elon Musk has called someone else an idiot on the internet. The world’s richest man and worst poster took some time out of his busy schedule of boosting white nationalist propaganda and denying that his chatbot was used in the widespread creation of nonconsensual sexual images to call the CEO of Ryanair an idiot for his disinterest in adding Starlink internet to his company’s flights.

The whole drama started when Michael O’Leary, the CEO of Irish budget airline Ryanair, told Reuters that his company wouldn’t bother making a deal with Musk’s Starlink to add satellite internet access to flights despite other airlines embracing it. His reasoning was pretty straightforward and two-fold: It’ll add fuel costs, and most people won’t buy internet on short flights. “You need to put antenna on fuselage, it comes with a 2% fuel penalty because of the weight and drag,” he told Reuters. “We don’t think our passengers are willing to pay for WiFi for an average 1-hour flight.”

That’s straightforward enough. But as has been well documented at this point, Musk does not respond well to rejection or critical feedback. So he did what he does about most things at this point and started tweeting about it. In a post, he called O’Leary “misinformed,” and claimed, “I doubt they can even measure the difference in fuel use accurately, especially for a one hour flight, where the incremental drag is basically zero during the ascent phase due to high angle of attack.”

Michael Nicolls, Starlink’s vice president of engineering, chimed in as well, posting, “A 2% fuel impact might be true for legacy terminals, but Starlink’s terminal is much lower profile and more efficient. Our analysis shows that the fuel increase to a 737-800 (which burns 800 gallons/hour) with our current design is about 0.3%.” There doesn’t appear to be much for third-party measurement of this, but Starlink’s antenna is less bulky than alternatives.

It seems possible that O’Leary and the Starlink crew are talking about slightly different things. Nicolls and Musk seem to be comparing the fuel efficiency of Starlink’s antenna to the bulkier antennas of other internet providers and concluding that the slimmer design of their company’s antenna is an improvement over the alternative. O’Leary, meanwhile, seems to be talking about the consequence of adding an antenna rather than not having any antenna at all.

In an appearance on the podcast The Hard Shoulder, O’Leary responded to Musk’s comments and cranked up the heat a bit on the whole situation. “What Elon Musk knows about flights and drag would be zero,” he said, adding, “We’ve already had Boeing confirm we have to put an aerial antenna on top of the aircraft. Now, that will cost us about a 2% fuel drag.” He claimed that the upgrade would add an additional $200 to $250 million a year in costs, which would be passed on to customers. This, he reasoned, was untenable because people won’t be interested in paying for internet service.

O’Leary’s claims might seem a bit ridiculous if you’re thinking about it in terms of American airline prices. But, according to Business Insider, Ryanair offers tickets for prices as low as 15 euros, or about $17. Most of those flights are short, under two hours, and charge for things like picking your seat. So a $1 difference actually might matter to his customer base. Starlink, which has been rapidly adding airlines to its list of customers, currently has deals in place to offer that internet service to travelers free of charge. But O’Leary seems to be saying that it’s not actually free if it adds fuel costs that get passed down to consumers in ticket prices.

To drive the stake in just a bit more, O’Leary concluded, “I would pay no attention whatsoever to Elon Musk. He’s an idiot. Very wealthy, but he’s still an idiot.”

As you’d probably expect, Musk didn’t let that slide. He fired back in kind on Friday, calling O’Leary an “utter idiot” in a post on X and demanding Ryanair fire him. And, as these cycles tend to go, someone replied to Musk and told him to buy Ryanair so he could fire O’Leary himself, to which Musk replied, “Good idea.” Most of the time, Musk claims he’s going to buy something to forcefully get an outcome he wants, but it’s just bluster. But not always (see: Twitter, America, etc.). But it seems bad that the threat even has to be considered.