Bell P-63 Kingcobra
- XP-63 Prototypes (two) (company designation was Model 24); USAAF serials (41-19511 and 41-19512).
- XP-63A Following the loss of the first two prototypes, an additional test aircraft was procured, USAAF serial 42-78015, originally ordered as a testbed for the proposed Rolls-Royce Merlin-powered P-63B.
- P-63A The production model Bell Model 33; 1725 P-63As produced in various sub-marks.
- P-63B Proposed Rolls-Royce Merlin-powered P-63B series was cancelled due to lack of availability of Merlin engines.
- P-63C Second production series differed from the P-63A by being powered by the uprated Allison V-1710-117 engine with a war emergency rating of 1,500 hp (1,120 kW) at sea level and 1,800 hp (1,340 kW) with water injection. The wingspan was reduced by 10 inches (250 mm). A total production run of 1,227 was completed.
- P-63D One aircraft (43-11718) powered by an Allison V-1710-109 (E22) 1,425 hp (1,063 kW) featured a 10 in (25 cm) wingspan increase (to 39 ft 2 in (11.94 m), gross area being increased to 255 sq ft (23.7 m2) and, most noticeably, a rearward-sliding bubble canopy. The series was cancelled in 1945.
- P-63E Essentially similar to the P-63D with the exception of a ventral fin extension and the use of a standard "cab"-style cockpit; only 13 built.
- P-63F Bell Model 43 variant featured an enlarged vertical tail and Allison V-1710-135; only two (43-11719 and 43-11722) built.
- RP-63A/C "Pinball" Target aircraft with five modified from P-63As and 95 modified on production lines; in 1948, surviving RP-63A aircraft were redesignated QF-63A. A further 200 production RP-63C aircraft were modified on the production line. Similarly, the surviving RP-63Cs were redesignated QF-63Cs. Many of the "target" aircraft were actually used as target tugs.
- RP-63G "Pinball" "Dedicated" flying targets which included two prototypes (43-11723 and 11724) and 30 production aircraft that incorporated a flush dorsal inlet but, more significantly, lights that would come on when the target was struck with frangible munitions. In 1948, the remaining RP-63Gs were redesignated QF-63Gs.
- L-39 Two war surplus P-63Cs modified by Bell under Navy contract for flight testing of low-speed and stall characteristics of high-speed wing designs.
- P-63 V-tail