Born on 29 October 1913 at Grodek Jagiellonski. According to his memoirs, upon graduation from the secondary school he joined a Catholic Seminary, but left it after two years of studies (before he was ordained). During his compulsory military service he volunteered to join the air force. Between August 1936 and August 1937 he underwent flying training at the 6th Air Regiment in Lwow. Subsequently he served with the regiment as a pilot. During March-July 1939 he was an instructor at the flying training school of the 6th Air Regiment. In September 1939 he failed to take part in fighting. He was evacuated do Rumania, and following a short internment he left that country by sea, arriving in Marseilles, France, in February 1940. By early 1940 he arrived in Britain. He received service no. 780485. After conversion training British aircraft and a short fighter course at No. 5 Operational Training Unit, Aston Down, on 10 September 1940 he was posted to No.111 Squadron RAF. Two weeks later he was reposted to No. 229 Squadron RAF. In thise units he fought in the Battle of Britain. On two occasions he was forced to make emergency landings: on 25 October in Hurricane I V6692, and on 30 October in Hurricane I V6685. On 25 February he was reposted to No. 317 Squadron, then forming. For his wartime achievements he was commissioned on 1 June 1942 (receiving an officer's service no. P-1912). On 28 August 1942 he was posted for rest from operations, becoming an instructor at No. 58 Operational Training Unit. On 23 March 1943 he resumed operational flying, posted to No. 316 Squadron. On 9 August 1943 he flew Supermarine Spitfire F.IX BS302 SZ-E within the entire Northolt Wing for Ramrod 191. About 18.30 over France he suffered a collision with Spitfire F.IX BS457 SZ-R of F/O Lech Kondracki. The latter pilot was killed and Maciejowski was injured, but managed to bail out and became a prisoner of war. He returned from captivity after the war ended, in May 1945. In August 1945 he was posted to No. 16 (Polish) Service Flying Training School, and on 14 November 1945 to No. 309 Squadron. He served with the unit as a pilot until its disbandment in December 1946. Following release from the Polish Air Force he joined the RAF as an officer (service no. 501923). He changed his name to Manson. Initially he served as an pilot, and later in ground trades. He retired at the age of 60 and lived near Liverpool. In 1987, after his wife died, he emigrated to live with his daughter in Canada. He died there on 26 April 2001.
His decorations included the Silver
Cross of Virtuti Militari (no. 09367),
the Cross of Valour and three Bars,
the Distinguished Flying Cross,
the Distinguished Flying Medal.