The “Zero-Launch” (ZELL) program by the USAF began as a way to get aircraft off the ground faster with shorter runways in an effort to avoid the vulnerability of attack on airfields. Testing began in the 1950s with the F-84. Later the larger F-100 was considered more suitable for the program.
“Testing proved that the F-100 was capable of a ZELL launch even while carrying both an external fuel tank and a single nuclear weapon mounted on its hard points. The conceived mission profile would have been for the pilot to have launched a retaliatory nuclear strike against the attacker before attempting to return to any available friendly airbase or having to eject from the aircraft if a safe landing site could not be reached.
Despite the extremely high thrust generated by the rocket motor, the F-100 reportedly subjected its pilot to a maximum of 4g of acceleration forces during the takeoff phase of flight, reaching a speed of roughly 300 mph prior to the rocket motor’s depletion. Once all fuel had been exhausted, the rocket motor was intended to slip backward from its attachment points and drop away from the aircraft. However, testing revealed that this would sometimes fail to detach or cause minor damage to the aircraft’s underside when doing so. Despite such difficulties being encountered, the F-100’s ZELL system was considered to be feasible, but the idea of its deployment had become less attractive as time went on.”
Eventually, all projects involving ZELL aircraft were abandoned, largely due to logistical concerns.
Here’s a 1958 video from Popular Mechanics….