Franjo Kluz (left on the stamp) was born in Jošik, near Bosanska Dubica.
In the second half of May 1942, like Rudi Čajavec before him, he defected to the Partisans with his Potez 25 aircraft. From the improvised airfield near Prijedor he carried out a number of sorties against Axis forces, the most notable being the attack on an Ustaša column near Orahovo on 4 June. His plane was destroyed by hostile fire on 6 July.
Kluz became a member of the 1st Air Squadron of YNLA, otherwise known as No. 352 Squadron RAF. On 14 September 1944, he was shot down in his Spitfire and killed by German AAA over Omiš. For his wartime service, Franjo Kluz was posthumously awarded the Order of a People's Hero of Yugoslavia.
Rudi Čajavec (right on the stamp) was a Yugoslav pilot, best known as the first airman of Partisan air force.
After Axis invasion of Yugoslavia and establishment of Independent State of Croatia he came to Banja Luka where he joined resistance movement. On 21 May 1942 he flew his Breguet 19 biplane and defected with his gunner Mišo Jazbec to Partisans. He landed near Partisan-controlled Prijedor.
Partisans immediately started to use their own plane. On 2 July 1942 Čajavec made an air raid on Banja Luka, which included strafing the local airfield, dropping bombs on important city buildings as well as leaflets on city streets. The plane was damaged by anti-aircraft artillery, and Čajavec was forced to crashland on territory controlled by Chetniks. After they have surrounded him, Čajavec committed suicide to avoid being captured.
Stamp is issued on 21.05.1985.