From Wikipedia....
"Prince George died on 25 August 1942, at the age of 39, along with thirteen others, on board RAF Short Sunderland flying boat W4026, which crashed into a hillside near Dunbeath, Caithness, Scotland, while flying from Invergordon, Ross and Cromarty, to Iceland on non-operational duties.
Lynn Picknett and Clive Prince alleged in their book Double Standards, which has been criticized for its "implausible inaccuracy", that Prince George had a briefcase full of 100-krona notes, worthless in Iceland, handcuffed to his wrist, leading to speculation the flight was a military mission to Sweden, the only place where krona notes were of value.
His death while in the service of the RAF marked the first time in more than 450 years that a member of the Royal family died on active service. The Prince's body was transferred initially to St. George's Chapel, Windsor, and he was buried in the Royal Burial Ground, Frogmore, directly behind Queen Victoria's mausoleum. His elder son, six-year-old Prince Edward, succeeded him as Duke of Kent. Princess Marina, his wife, had given birth to their third child, Prince Michael, only seven weeks before Prince George's death.
One RAF crew member Flight Sergeant Andrew Jack, the Sunderland's rear gunner, survived the crash on Eagle's Rock near Caithness. His niece has claimed that Jack told his brother that the Duke had been at the controls of the plane; that he had dragged him from the pilot's seat after the crash; and that there was an additional person on board the plane whose identity has never been revealed."