Based on the single-engine Focke-Wulf A 16 with the nose faired over and fitted with two wing-mounted 58 kW (78 hp) Junkers L.1a radial engines, the GL18 had an enclosed cabin for a pilot and four passengers. The GL18 first flew on 9 August 1926 and was used by Deutsche Luft Hansa until 1932. The next aircraft was the GL 18a variant with two Siemens Sh 11 engines which was followed by the GL 18c with two Siemens Sh 12 engines. The 18a and 18b had slightly wider fuselage. In 1927 a modified Siemens Sh 12 engined variant the GL 22 was produced, it had a deeper fuselage, the engines were mounted underneath the wings and it had a revised landing gear.