Over the 1960s, the airline saw a significant growth, concerning both its route network and fleet of Soviet-built aircraft. The Ilyushin Il-18 turboprop airliner became the backbone of Interflug's short haul flights during that period. The company had been the intended primary operator of the Baade 152, an early jet airliner constructed in East Germany.[5] The development never went beyond the prototype phase, though, and was abandoned in 1961.