Douglas confirmed the feasibility of the concept and the USAAF amended the XB-42 contract in March 1944 to include the development of two turbojet-powered XB-43 prototypes, reduced from an initial order of 13 test aircraft.

Without any propellers present, there was no chance of striking the blade tips on the runway, so the entire ventral fin/rudder unit of the earlier XB-42's full four-surface cruciform tail was omitted.

The USAAF was already moving ahead with a new bomber, the XB-45 Tornado, designed from the outset for turbojet power and promising major improvement in every category of performance.

As Douglas predicted, the work itself was not overly complex but almost two years were required to ready the aircraft for flight due to delays in obtaining the J35 powerplants.

Caught in a momentous technological shift, the XB-43 contributed to developing procedures for flying the new jet bombers, and it gave yeoman service testing new turbojet engines.

Douglas completed the second prototype, AAF serial number 44-61509, flying on 15 May 1947 and delivered it to Muroc Air Force Base, California, in April 1948.

When the clear plastic nose began to crack from variations in temperature at high and low altitudes, mechanics fashioned a more durable replacement made from plywood.