Shotgun, 12ga, birdshot, no choke. Maybe Federal Flight Control shells. Tough shot if it's moving laterally and more than 50' away (esp. with no choke!), but a pellet through the right place is going to knock it down, or mess the controls up enough that it's not functional anymore.
You definitely want something a bit longer than a trenchgun for this though.
Shotgun, 12ga, birdshot, no choke. Maybe Federal Flight Control shells. Tough shot if it's moving laterally and more than 50' away (esp. with no choke!), but a pellet through the right place is going to knock it down, or mess the controls up enough that it's not functional anymore.
You definitely want something a bit longer than a trenchgun for this though.