Put a riding crop/carrot on a stick on the following character, but NOT the leader.

Due to inevitable lag, if you're always flying in a straight line eventually your /follower will kick the bucket. Speed increasers like riding crop help increase the time before it happens. Just make sure that you either make a few turns once in a while or stop every second or two to allow the /follow to ride your ass once more.

Suvega has 5 epic mounts now and without speed increasers on his followers, his characters get lots almost immediately.