The Prince of Wales surprised helicopter staff on Friday after making an unannounced visit to a base in Oxfordshire.
Prince William, 42, turned up at the official opening of the new Airbus Helicopters headquarters at Oxford Airport, it is reported.
His appearance was not announced in advance and it is understood he was there in a private capacity.
According to The Telegraph newspaper, he was invited by Airbus because of his connection with London Air Ambulance, of which he is a patron.
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He reportedly attended wearing a blue jumper and spoke informally with staff.
He was also shown around the newly delivered Airbus H135, bound for London Air Ambulance, which was on display in the hangar.
The helicopter is an updated version of the aircraft the Prince flew during his two years as a pilot with the East Anglian Air Ambulance between March 2015 and July 2017.
William also served as a RAF search and rescue pilot.
His eldest son, Prince George, is said to have been fascinated with aircraft since he was a toddler.
Airbus has been contacted for comment.
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