This was a relatively new concept, as jet aircraft had only been around since the middle-to-final stages of the Second World War, but that didn’t stop the US Air Force and Navy from ordering the development of the Bell D-188A. With a desire to develop a fighter aircraft that could be operated from virtually anywhere, the US Air Force and Navy approached Bell Aircraft to design one. While the Bell D-188A wasn’t directly replaced by another aircraft, its cancellation allowed for the development of more practical VTOL technology.