By the time the Germans invaded in 1941, the Ilyushin Il-4 had already been a tried and tested aircraft having flown extensively during the Winter War of 1940. By Russian standards the Il-4 was a strategic bomber albeit much smaller than it's western counterparts which would have considered it a medium bomber instead. It managed to bomb Berlin during the summer of 1941 (the first Soviet aircraft to do so) and was used well up until 1945 and the post-war era even though production had ceased a year earlier. Despite it's good range, the Il-4 was poorly protected and suffered heavy casualties even from mediocre Finnish aircraft like the Gladiator or Fokker D.XXI although this was compensated by its versatility which allowed it to perform roles like glider tug, transport and reconnaissance in addition to maritime duties with Soviet Naval Aviation. A number of captured examples found themselves flown by Finland.

The prototype of this aircraft was designated TsKB-26 and took its maiden flight as early as May 1936 with production commencing in 1937 as the DB-3 with an open cockpit. Production switched shortly after to the DB-3B with a more powerful engines and closed cockpits, later the definitive DB-3F or Il-4 appeared. These featured yet another engine upgrade as well as a redesigned nose and were immediately put into mass production. Due to a shortage of strategic materials, many Il-4s had extensive use of wood in the structure in place of metal parts.