Definition: To "air" in skateboarding is to get into the air without ollying. Usually, this is done by simply riding off the end of a ramp or jump.
Sometimes, skaters will talk about airing things - like airing a gap. This means that they rode their skateboard off of a ramp or anything else and jumped over a gap, without ollying.
Air can also be used to refer to how high someone got with a trick, saying that they "got lots of air".
Examples:
"Marcy sped towards the jump and flew off the end, totally airing over Billy who was laying down at the end of the ramp."
