Pig Planes

Not to be confused with Shark Ships from Angry Birds 3: The Final FlocktierPig Planes are a type of pig enemy only found in Angry Birds: Bubbles. The first and last appearance of the planes was in Pigs can Fly. These enemies are different as they only appear in tower defense levels in Pigs can Fly. They appear in 12-4, 12-6, and 12-9. They carry around pigs who can't fly and acts as an enemy to destroy.

Strategy
Place as many offensive towers around the planes, and easily cripple it.