Royal surprise: Dutch King Alexander was KLM pilot for 21 years

May 18 (UPI) -- Dutch King Willem-Alexander dropped a bombshell Thursday -- he's secretly piloted commercial flights for KLM Royal Dutch Airlines for more than two decades.

The reigning monarch, 50, who first learned to fly as a student and later in the Royal Netherlands Air Force, told Dutch newspaper De Telegraaf he has been a part-time co-pilot for the flagship carrier on short, inter-city flights for 21 years.

"For me the most important thing is that I have a hobby for which I need to concentrate completely," he said. "You have an aircraft, passengers and crew. You have responsibility for them. You can't take your problems from the ground into the skies. You can completely disengage and concentrate on something else. That, for me, is the most relaxing part of flying."

As king, he was a pilot for the Dutch cargo airline Martinair, and later flew Fokker 70 aircraft for KLM. With the airline's phase out of the Fokker planes, Willem-Alexander is retraining as a Boeing 737 pilot.

The king added that passengers rarely recognize him on flights -- and when he speaks to the passengers onboard, he does it anonymously.

"The advantage is that I can always say that I wish everyone a heartfelt welcome in the name of the captain and the crew, so I don't have to say my own name," he said. "But most of the [passengers] don't listen anyway."

Britain's Prince Charles is also a qualified pilot, and his sons, William and Harry, flew helicopters during their military careers. Hassanal Bolkiah, the sultan of Brunei, also occasionally takes the controls of the plane while traveling on state visits.