In 1930, workshops were completed at the airfields at Zagreb and Mostar, allowing for repairs and modifications to be carried out without transferring aircraft to the main factories and workshops closer to the capital. In May of that year, the first aircraft of entirely Yugoslav manufacture was completed at Kraljevo, and it was estimated that factory was capable of producing 100 Breguet 19 aircraft per year. At this time, the factory had a French workforce and was under French management, but the contract was due to expire in 1932, after which the Yugoslav government would be at liberty to produce whichever aircraft it could obtain licences to build. The privately owned Ikarus plant at Zemun continued to produce seaplanes of its own design as well as Potez 25 aircraft under licence. The strength of the air force was estimated at 26 squadrons of about twelve aircraft each, indicating a total of approximately 312 aircraft, although there were almost no reserve aircraft.
