Answer: Royal Flying Corps
"The Story of Vernon and Irene Castle" tells the story of the titular couple who, prior to the First World War, were famous around the world for their dancing. In 1916, having qualified as a pilot, Vernon Castle enlisted in the Royal Flying Corps, serving on the Western Front until 1917, when he was transferred to Canada. In February 1918, while on a training flight in Texas, his aeroplane crashed and he was killed. The film of their story had a number of elements to it that Irene Castle, despite serving as a consultant, did not approve of. A major departure from the previous films that Astaire and Rogers had made, in that it was a (fictionalised) biopic, with the pair playing an already married couple, and with a tragic ending, the film went on to lose $50,000 as a result of its high costs. By the time of its release, the pair had elected to end their working relationship - while Ginger Rogers remained under contract at RKO, going on to win an Academy Award for the 1940 film "Kitty Foyle", Fred Astaire left RKO to work as a freelance performer, appearing in pictures for a number of different studios. Ten years after "The Story of Vernon and Irene Castle", Astaire and Rogers reunited one final time in the MGM musical "The Barkleys of Broadway".