In an interview with newspaper De Telegraaf, Willem-Alexander, 50, calls flying a "hobby" that lets him leave his royal duties on the ground and fully focus on something else.
"You have an aircraft, passengers and crew. You have responsibility for them," the king told De Telegraaf. "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."
The Dutch king was a "guest pilot" on the KLM's fleet of Fokker 70 planes and before that on Dutch carrier Martinair.
As Fokker aircrafts are being phased out of service, the king is now training to fly Boeing 737s.
It was widely known that Willem-Alexander had a passion for flying, but this is the first time that the frequency of those flights is revealed.
Before 9/11, when airlines frequently kept the doors to the cockpit open, passengers were more likely to spot Willem-Alexander as their co-pilot.
"People regularly came to have a look and thought it was nice or surprising that I was sitting there," he said
However, things have changed since the attack, plane security was increasingly tightened.
The king never uses his name when addressing passengers and few people recognize him in uniform and wearing his KLM cap.
Surprisingly though, he admitted that some people had recognized his voice.
"The advantage is that I can always say that I warmly welcome passengers on behalf of the captain and crew," he said. "Then I don't have to give my name."
Royals who married commoners
Royals who married commoners
Letizia Ortiz Rocasolano and King Felipe VI
Letizia Ortiz Rocasolano, now Queen Letizia of Spain, was a journalist and news broadcaster. She reported on the 2000 U.S. presidential election, and was an anchor of the nightly news program Telediario. In 2003, she became engaged to Felipe, who was then Prince of Asturias. The engagement was seen as a surprise not only because of her nonroyal status, but also because she had been previously married.
Charlene Wittstock and Prince Albert II
In the summer of 2011, Charlene Wittstock married long-time bachelor Prince Albert II of Monaco—the son of Princess Grace Kelly and Prince Rainier III. Wittstock, who is now Princess of Monaco, was born in what is now modern-day Zimbabwe. She moved with her family to South Africa during her childhood, and later represented the nation as a swimmer in the Olympics.
Sofia Hellqvist and Prince Carl Philip
Sofia Hellqvist married Prince Carl Philip of Sweden in 2015. She is now known as Princess Sofia of Sweden, Duchess of Värmland, but was a model and reality-TV star prior to her marriage. The couple’s first child together, Prince Alexander, was born this past April.
Victoria, Crown Princess of Sweden and Daniel Westling
Sweden’s Crown Princess Victoria met her husband, Prince Daniel, while he was working as her personal trainer. Before this, he had served in the Swedish Army. The couple announced their engagement in 2009, and wed in June of 2010.
Princess Madeleine of Sweden and Christopher O’Neill
Princess Madeleine, the sister of Sweden’s Crown Princess Victoria and Prince Carl Philip, married Christopher O’Neill in 2013. O’Neill is an American-British financier. He was born in London, and attended college at Boston University, where he majored in international relations. O’Neill does not hold a title, and he declined Swedish citizenship. As a private citizen, he has been able to continue his career in finance.
Masako Owada and Crown Prince Naruhito
Masako Owada was born in Tokyo, Japan, but moved with her family to the U.S. while she was in high school. She attended Harvard University, where she studied economics. She went on to study at Oxford and at the University of Tokyo as well, with a focus on international relations and law. Owada, now Crown Princess of Japan, has been married to Crown Prince Naruhito for more than 20 years. They have one daughter, Princess Aiko.
Rania Al-Yassin and King Abdullah II of Jordan
Now Queen Rania met then-Prince Abdullah of Jordan when she was 22 years old. Queen Rania was born in Kuwait to Palestinian parents: Her family fled to Jordan around the time Kuwait was invaded by Saddam Hussein. She studied at the American University in Cairo, and worked briefly at Citibank and Apple. She and her husband became King and Queen of Jordan in 1999.
Máxima Zorreguieta Cerruti and King Willem-Alexander of the Netherlands
Máxima Zorreguieta Cerruti was born in Buenos Aires, Argentina, and was working at Deutsche Bank in New York City when she met then-Prince Willem-Alexander of the Netherlands in 1999. The couple met in Seville, Spain, at a fair, where the prince introduced himself simply as “Alexander.” Máxima, who is descended from Iberian royalty though born a commoner, is now Queen of the Netherlands.
Marie-Chantal Miller and Pavlos, Crown Prince of Greece
Marie-Chantal is one of the three famous Miller sisters. (Her sister Pia married a Getty, and Alexandra Miller was married for a time to Diane von Furstenberg’s son.) Their father, Robert Warren Miller, made his fortune through his empire of duty-free shops. Marie-Chantal married Crown Prince Pavlos of Greece in 1995. She is now styled as Crown Princess of Greece, Princess of Denmark, and has five children.