Timeline

May 1969

Biafrans commence land offensive reinforced by foreign mercenary pilots, attacking military airfields in Enugu, Port Harcourt, Ughelli, and Benin City

By the end of the Nigeria -Biafra war, Biafra’s territory was approximately 10 percent its original size, and even by 1969, the Biafran enclave was already much smaller than it had been at the start of the war. In the middle of 1969, the Biafrans began a series of land offensives attempting to destroy military airfields in certain strategic cities, including Enugu, Port Harcourt, Ughelli, and Benin City.

Foreign mercenaries aided the Biafrans efforts, specifically Swedish mercenaries, including Count Carl Gustav von Rosen, Gunnar Haglund, and Martin Lang. The foreign mercenaries, accompanied by two Biafran pilots, were attempting to destroy the Nigerian aircraft that were attacking relief planes delivering humanitarian aid and resources to Biafra. Von Rosen, along with the four other pilots, named their planes the “Biafran babies” because of the thousands of Biafran children who were starving because of the Nigerian blockade.

The offensive was successful at destroying some Nigerian aircraft, but it did not turn the tide of the war.

Carl Gustof von Rosen, Swedish pilot who worked for the United Nations before becoming a mercenary pilot. He flew for Biafra, then flew aid into famine-stricken Ethiopia from 1974-77. He was killed in 1977, during the war between Ethiopia and Somalia.
See Also:

Interview with Count Carl Gustaf von Rosen, September 7, 1969, AP Archive, uploaded July 21, 2015.

Maubec, Paul. “Swedish Pilots Fly 5 Planes to Biafra.” The Washington Post, September 8, 1969.

Sources: http://fly.historicwings.com/2012/07/count-von-rosens-air-force/; https://face2faceafrica.com/article/carl-gustaf-von-rosen-biafran-war