Some B-29s were converted to carrier aircraft and used to air-launch experimental aircraft in the years following World War II. The bomb bay was modified to accept the experimental aircraft, which was mated to the B-29 "mother ship" on the ground and flown to a specified altitude where the test aircraft was released.
One aircraft was converted to carry the Bell X-1 series test aircraft and was used until replaced by a more modern Boeing B-50.
Another EB-29 was used carry the XF-85 and test the parasite fighter concept. The XF-85 Goblin parasite aircraft was developed to protect B-36 bombers flying beyond the range of conventional escort fighters. In theory, a B-36 penetrating enemy territory would carry its protecting fighter in the bomb bay. If attacked by enemy aircraft, the bomber would lower the Goblin on a trapeze and release it to combat the attackers. After the enemy had been driven away, the parasite fighter would return to the bomber, hook onto the trapeze, fold its wings and be lifted back into the bomb bay. Although the XF-85 was successfully launched and retrieved from an EB-29B on several test flights, it was never flown from a B-36. The test program was canceled in late 1949 when mid-air refueling of fighter aircraft for range extension began to show greater promise.