Developed from the Douglas XSB2D-1 Destroyer as a torpedo bomber for the US Navy, the Douglas BTD Destroyer first flew on 5 March 1944. It differed from the XSB2D-1 with the removal of the turrets and second crewman, the addition of more fuel and armor and wing racks that could carry two torpedoes.
The additional weight from the modifications severely affected performance and the contract was terminated at the end of the war, with only 26 production aircraft being completed.
Two XBTD-2 prototypes were built in an attempt to increase performance with the additional Westinghouse 19B engines in rear fuselage giving 1,500 lbf (6.7 kN) thrust. This mixed propulsion with the additional turbojet did not sufficiently improve performance to warrant production.
The Bloch MB.135 made its maiden flight on 12 January 1939. A development of the Bloch MB.131, it was designed as a medium bomber for the French Air Force. Heavily redesigned, it bore little resemblance to the MB.131 it was derived from. It was developed in parallel with the twin-engined MB.134 bomber version.
Despite promising performance, it was not entered into production, as it did not represent a sufficient improvement of existing bombers (the LeO 45 and Amiot 350).
The Bloch MB.134 made its maiden flight on 22 July 1939. A development of the Bloch MB.131, it was designed as a medium bomber for the French Air Force. Heavily redesigned, it bore little resemblance to the MB.131 it was derived from. It was developed in parallel with the four engined MB.135 bomber version.
A landing accident on 21 April 1940 resulted in seriously damage when a landing gear strut collapsed following the in-flight failure of a hydraulic fluid reservoir. With the fall of France it was not repaired and no further development took place.