An aerial attack is any attack that is performed in midair that is not a special move. Their official terms vary between titles; they are known as midair attacks in Super Smash Bros. Melee, and air attacks in Brawl and Smash 4. Aerial attacks play an especially large role in competitive play because they can be L-canceled and can be performed after a short hop, greatly reducing their lag and start-up time as compared to ground attacks. Not to mention making use of aerial momentum is a crucial part in making most aerial attacks good spacing tools. Most aerial attacks deal moderate damage (9%-14%-ish).
Aerial attacks include the:
Gliding characters also possess a glide attack, which is used when attacking out of gliding.
Also, characters with a tether recovery or a wall-grapple usually possess an extra aerial attack, which is used by pressing the grab button.