R-22 Spearhead was a fast starfighter design that served as the basis for the RZ-1 A-wing interceptor.
The prototype R-22 Spearhead was broadly similar in design and function to the earlier Republic Delta-7 Aethersprite-class starfighter and Eta-2 Actis-class interceptor. A two-seat version was also produced, following the lineage of the Delta-12 Skysprite-class two-seater; some of this variant were used by the forces of Tammuz-an.
The Spearhead was in use by private owners and several defense forces all around the galaxy, like the Tammuz-an defense forces, where they escorted ships in the shipping fleet, and on Abridon at the Abridon Shipyard in Sayan.
The R-22 Spearhead became an experimental testbed for the Rebel Alliance, nicknamed the "A-wing," shortly before the Battle of Yavin. During one early operational test, the Rebels sent a lone R-22 to attack an unguarded Imperial repair dock. The fighter performed admirably, destroying the facility before the Nebulon-B frigate Virulence could respond. The mission was later recreated as a simulation used in training new pilots.
The Alliance Fleet started deploying a number of R-22s at that time. Captain Juno Eclipse and PROXY used a two-seater R-22 to travel to Dac to help Admiral Gial Ackbar and Senator Bail Organa liberate the Mon Calamari and recruit them to the Alliance cause. The fleet used them in the Assault on Kamino against the Imperial TIE/sa bombers. Keyan Farlander flew Spearheads in several missions during Operation Skyhook, and at least two R-22s participated in the Battle of Yavin, one piloted by Jake Farrell.
The Spearhead was nicknamed "A-wing" among Rebel pilots. The name "A-wing" persisted when the model was modified by General Jan Dodonna and Walex Blissex after the Battle of Yavin into the Rebel Alliance's fast RZ-1 A-wing interceptor.
What those modifications entailed and how they differed from the Spearhead is unknown, though it is known that Dodonna's decision to create the RZ-1 was largely driven by the Alliance's lack of a starfighter that could match the TIE/LN starfighter's raw speed. Additionally, the RZ-1 was also noted for its improved maneuverability, therefore the difference lies most likely in the engine design.
In addition to better engines, the weapons complement might have undergone a similar change, as early Spearhead-models were noted as using green laser ammunition rather than the red/orange seen with most Alliance fighters.