In an interview published by the Dutch De Telegraaf daily on Wednesday, King Willem-Alexander of the Netherlands said he is a regular “guest pilot,” or co-pilot, on KLM’s fleet of Fokker 70 planes. King Willem has piloted the Fokker for 21 years, first for Martinair and then for KLM. His passengers did not know, most of the time. He will not retrain to fly Boeing 737 as the Fokker fleet is being retired.