The Dutch King has been secretly flying passengers on commercial flights without anyone knowing.
For 21 years, King Willem-Alexander has flown twice a month as a co-pilot.
"I find flying simply fantastic," he told newspaper De Telegraaf.
So far he's stuck to Fokker planes, but in the coming months he plans to learn how to fly Boeing 737s.
"It also seemed nice to fly to other destinations one day, with more passengers and bigger distances. That was the real motive for training on the 737," he said.
He said if he wasn't born into royalty, he would have become a pilot. He finds flying relaxing, compared to his day job.
"You have a plane, passengers and crew and you are responsible for them. You can't take your problems with you off the ground. You can completely switch off for a while and focus on something else."
As a co-pilot, he hasn't been required to tell passengers his true identity.
Other unlikely commercial pilots include Bruce Dickinson, lead singer of metal veterans Iron Maiden, the Sultan of Brunei and King Abdullah of Jordan.