The North American B-45 Tornado was the United States Air Force's first operational jet bomber, and the first jet aircraft to be refuelled in the air. (US Air Force Photo)
The B-45 began development in 1944, when the War Department, alarmed by German jet bombers like the Arado Ar 234, called for a new family of jet bombers grossing between 80,000 and 200,000 pounds. (US Air Force Photo)
The first flight of the XB-45 was on March 17, 1947 from Muroc Army Air Field (Edwards Air Force Base). A total of 131 test flights were flown by the three prototype aircraft. (US Air Force Photo)
The B-45 was an important part of the United States's nuclear deterrent for several years in the early 1950s, but was rapidly succeeded by the Boeing B-47 Stratojet. (US Air Force Photo)
Four B-45s have survived to the present day. They are located at: Castle Air Museum in Atwater, California - Pima Air and Space Museum in Tucson, Arizona - National Museum of the United States Air Force near Dayton, Ohio - Strategic Air and Space Museum in Ashland, Nebraska.