10/31/2010. Remarks by Johan Visschedijk: "The Call brothers designed their first aircraft just before the war and the prototype Model A (c/n 1) first flew in 1940, powered by an 80 hp Continental engine and registered N27251. This aircraft was a side-by-side two-seat cabin monoplane with a strut-braced low wing and fixed tail wheel landing gear. In its initial form, the Model A was underpowered and the Model A-1 production version, certificated on July 26, 1944 was upgraded to an 100 hp Lycoming O-235 engine which gave it much better performance when operating from the high altitude of Callair's Afton, Wyoming base. Four (c/n 2 to 5) were built by the company between 1944 and 1945, the first was registered N26500.

The Models A-2, A-3 and A-4 followed and these all shared a similar airframe to the Model A-1 but with a smaller vertical tail and a variety of engines. 31 two-seat Models A-2 and A-3 (c/n 6 to 8 and 109 to 136) were built between 1946 and 1952, the sixteen Model A-2 were powered by an 125 Lycoming O-290-A engine, while the fifteen Model A-3 were powered by an 125 hp Continental C-125-2 engine. The similar Model A-4, introduced in 1954 and powered by an 140 hp Lycoming O-290-D2 engine, was able to carry three people on its main bench seat. This aircraft marked the expansion of the company's activities, and 65 Model A-4 were produced."