Welcome to the board.
The "snapping at mid air" is call flycatching, and can be a symtom of many things, from epilepsy to mere boredom.
Your dog is very young - what kind of exercise does he get? Do your work your dog on sheep, or does he have some sort of job?
Border collies are serious working dogs and if not worked or given a job (even something like agility or flyball training) can sometimes exhibit some strange behaviors or compulsions.
Of course this could also be a neurological problem. If testing is too expensive then you might try working your dog to see if his behaviors lessen. If they don't then some testing may be needed.
I"m sure others here will have some input as well!