I seem to recall an old Air Trails Hobbies for Young Men, or one of it's sucsessors pushing the event in the mid to late fifties maybe. They even had a couple sets of plans in their, I think Timely Plans service. I think I may still have a mag or two in a box in my attic. If I remember, they had four events to be flown with the same plane/engine/tank combination; speed, endurance, stunt, and either combat or baloon bust.
Almost forgot; the baloon bust I remember from that time period had baloons set in a row after an obstacle. You had to pass over the obstacle, the baloons closer to the obstacle were worth more than the ones farther away