Flight numbers are a set of 4 numbers that describe the shape of a disc's flight. They are almost always in the following order and printed on the front of most discs. The flight numbers are primarily a result of the disc's mold, it's physical shape.

Speed: How fast you need to throw the disc for the rest of the flight numbers to hold true.

Glide: How long the disc stays in the air.

Turn: High speed movement early in the flight.

Fade: Low speed movement late in the flight.