sentences:  It first flew in 1934 as a mailplane for Lufthansa but due to its narrow fuselage (hence its nickname) it was not commercially viable and was passed over.Dornier then developed it further as a military aircraft, with a prototype bomber flying in 1935, and in 1937 it was used in by the German Condor Legion during the Spanish Civil War.Production continued in Germany and it was developed to fill multiple roles for the Luftwaffe.