Complex sentence: They moved immediately to intercept making overhead runs on the slower, comparatively ungainly twin-engine bombers, and knocked out 3 of the 5 with their first pass--two for Fleming and one for his wingman.
Split into simpler sentences: They moved immediately to intercept, making overhead runs on the slower, comparatively ungainly twin-engine bombers. They knocked out 3 of the 5 with their first pass--two for Fleming and one for his wingman.