Following the war, he returned to printing, but yearned to return to flying. In 1926, he closed his print shop in
Eschweiler and became a flight instructor with the
Raab-Katzenstein aircraft company in
Kassel and continued to hone his flying skills, becoming an accomplished stunt pilot. In 1927, he performed a particularly daring routine in
Zürich and started to command increasingly high fees for appearances. In 1928 while working at
Raab-Katzenstein, he designed his own stunt plane, the
Fieseler F1 (also known as the
Raab-Katzenstein RK-26 Tigerschwalbe), which was offered and sold to a Swedish company called AB Svenska Järnvägverkstäderna (ASJ), which built 25 of the type for Swedish Air Force in the beginning of the 1930s. In 1930, Raab-Katzenstien was bankrupt, and Fieseler decided to strike out on his own. Using money he had been saving from his aerobatics, he bought the Segelflugzeugbau Kassel
sailplane factory and renamed it
Fieseler Flugzeugbau. Although he continued with some sailplane manufacturing, from 1932, he set up to start manufacturing sports planes of his own design. A
NSDAP member, Fieseler won contracts to licence-build military aircraft for the new
Luftwaffe in 1935. Real success came the following year, when his firm won a design contract against entries from
Messerschmitt and
Siebel for a
STOL liaison/observation plane, that his firm then went on to produce as the
Fieseler Fi 156 Storch. ==World War II==