From Sonic Retro
Egg Flappers are the one of the most common enemies in the game besides the Egg Pawns themselves. They resemble airplanes and use jet engines to keep themselves afloat. The easiest way to destroy them is with Thunder Shoot. There are many different kinds of flappers that are equipped with different weapons and come in a variety of colors.
List of Egg Flappers
The basic Flappers, along with their ground-based compatriots the Egg Pawns, make a nuisance out of themselves in Sonic Rush; particularly in Altitude Limit, where they get quite lethally in the way of rocket-pad steering. The drones can also be found in the game's Special Stages, where they can be destroyed by homing attacking them with the DS stylus.
Egg Flappers make an appearance in the Dream Gliding event in Mario & Sonic at the Olympic Winter Games. The point of the game is to shoot down the Flappers while riding a hang glider. They come in red and gold. Red Flappers are worth two points and Gold Flappers are worth five points.