King Willem-Alexander of the Netherlands has been on the throne since 2013 and, since he was a child, interested in aviation. This isn’t exactly a secret, since he once publicly appeared as a guest pilot on a KLM commercial flight. The secret is just how into it he truly is.

A Fokker 70.
A Fokker 70. Arpingstone/Public Domain

In 2017, Willem-Alexander revealed that in fact he had been secretly copiloting passenger flights for 21 years, including several during his reign. “I find flying simply fantastic,” he told De Telegraaf, according to the BBC.

The king never tried to hide his presence in the cockpit. He said he just never identified himself explicitly to KLM passengers, even if some may have recognized his voice during announcements.

A Boeing 737-200 cockpit.
A Boeing 737-200 cockpit. Sergey Ryabtsev/GNU

What did the king fly? Mostly Fokker 70 aircraft. But Fokker, the Dutch company that made the model, went out of business in 1996, meaning that the 70 was being phased out. At the time of his annoucement, Willem-Alexander said he would try his hand at flying the Boeing 737 next.

Godspeed, King Willem-Alexander.