In the summer of 1941, Roosevelt searched for and located air base sites in Labrador, Baffin Island, and Greenland and reported on conditions in Iceland and along the rest of the embryonic North Atlantic ferry route. During this time, he coordinated closely with FDR, Prime Minister Winston Churchill, and General Arnold. Elliott Roosevelt was the first to interest Churchill in American bases in Africa (first, Bathurst in the Gambia, now Banjul), a step for which his father was not yet ready. He served as a procurement specialist, navigator, and intelligence and reconnaissance officer and rose to Brigadier General by January 1945. Despite having poor eyesight and being classified 4-F (unfit), he also became a pilot and reportedly flew 89 combat missions by the time of his inactivation from the United States Army Air Forces (USAAF) in August 1945.
Following threats of resignation and pressure from "very high topside," in January 1945 General Arnold ordered General Carl Spaatz in England to appoint Roosevelt a rated pilot, and the President submitted his son's name to the Senate for promotion to brigadier general. By standard rules, Roosevelt was eligible for the rank, but not for the pilot's wings. Roosevelt continued in that rank in Europe until his father's death on April 12, 1945. After VE-Day, the Air Forces could no longer find a "suitable vacancy" for him, and he was on leave and had staff duties in the United States. By coincidence, his last day of service was VJ-Day.
Roosevelt stated that he flew 89 combat missions and 470 combat hours prior to being called back for his father's funeral in April 1945 (he did not return to active theaters). His decorations included the Distinguished Flying Cross. He also received the Order of the British Empire, the Croix de Guerre and Legion d'Honneur, the Moroccan Order of Ouissam Alaouite, and the U.S. Legion of Merit. He ended the war holding the Air Medal with reportedly eleven clusters. As a chase pilot for the Operation Aphrodite flights in 1944, Roosevelt said he witnessed the death of Joseph P. Kennedy, Jr. over Blythburgh, England (there is no evidence in Aphrodite files that Roosevelt participated in this project, nor did he fly as chase pilot and witness the death of Joseph P. Kennedy).
After FDR's death in 1945, Roosevelt and his family moved to Top Cottage to be near his mother, who considered him her favorite child. She gave him financial assistance throughout her life. In 1947, Eleanor bought from the FDR estate Val-Kill farms, the home she lived in after FDR's death, and deeded the property to Elliott Roosevelt. After he moved to Miami Beach and Havana with his fourth wife in 1952, his brother John bought the Hyde Park tract. Later, the property became Eleanor Roosevelt National Historic Site.