WWI aerial combat began with improvised pilot ingenuity before dedicated weapons.

Evidence

The problem was that both sides appreciated the significance of aerial reconnaissance, and each attempted to prevent the other from gathering it. It didn’t take long before planes from one side started encountering planes from the other, and pilots tried all sorts of clever tricks to force their opponents from the sky. Some hurled bricks at the cockpits of enemy planes; others dangled strands of rope or chain in front of the propellers. Many started carrying pistols, firing at enemy pilots as they flew past. — Emlen, Douglas J, Animal Weapons_ The Evolution of Battle, 540