By the end of 1944, the Lavochkin bureau had abandoned further development of the mixed-construction La-7 in favour of an entirely new all-metal design bearing only a configurational similarity to its predecessor, and, early in 1945, work began on this as the La-126. The La-126 possessed no commonality with the Lavochkin bureau's previous La-7 fighter, apart from an M-82FN (ASh-82FN) engine. It featured an all-metal monocoque fuselage and a TsAGI laminar-section wing. Armament was restricted to two 20mm ShVAK cannon and prototype flight testing was completed at the factory on 10 January 1945, but no production was undertaken, the La-126 serving as a basis for the La-130.
The prototype was subsequently fitted with two Bondaryuk VRD-430 ramjets as the La-126PVRD, and these, it was claimed, increased maximum speed in level flight by 100km/h. The La-126PVRD was tested between June and September 1946, attaining a max speed of 800km/h at 8000m.