Notable missions of the Oil Campaign of World War II included bombings of the Ploesti Concordia Vega refinery on 18 May 1944, the marshalling yards and oil refinery at Vienna on 8 July 1944 (1st DUC), and the Pardubice oil refinery and nearby railroad tracks on 24 August 1944 (2nd DUC).
From January 1944 until May 1945, the P-38s of the 82d Fighter Group struck oil centers at Ploesti in Rumania, Blechhammer in Poland, Vienna in Austria, Dubova in Czechoslovakia, as well as in Hungary, France, and Yugoslavia.
Serving in North Africa during World War II, he was promoted to Master Sergeant, and on August 1, 1943, he flew in Operation Tidal Wave, a bombing raid on the Romanian oil refineries of Ploeşti, which were a major source of oil for the Nazi war machine.
German Chancellor Adolf Hitler had received over 80% of his oil and gas supplies from Ploesti.
Working with acrylic paints on wooden cut-outs and transparent polyester resin small sculptures, Crist created images reminiscent of her childhood at her family's country estate, Ograda, near Ploesti.
Lt. Col. Addison E. Baker, group commander, and Major John L. Jerstad, a former member of the group who had volunteered for this mission, were posthumously awarded the Medal of Honor for action in the Ploesti raid.
Jagdgeschwader 4 was still only a single Gruppe in strength at the time and had been set up to provide air protection against bombing raids on the vital Ploesti oil refineries, north of Bucharest.