Complex sentence: South African air assets were moved from their missions in Culuvai to Caiundo but by the end of hostilities in January, the air and ground attacks had failed to dislodge FAPLA from the towns defenses.
Split into simpler sentences: South African air assets were moved from their missions in Culuvai to Caiundo. By the end of hostilities in January, the air and ground attacks had failed to dislodge FAPLA from the towns defenses.