It’s definitely in the character movement component of your character.
There are a few things regarding friction but I’m not sure if that applies to flying. Check around in the settings for the CMC (Character Movement component)!
Why wouldn’t the nodes / programming (method to control speed) in the flying sample be used with a character class? The character class has additional defaults that do more things then the pawn… so, if the pawn has the speed functionality, they should work in the character. Load up the flying sample…