Horse biting at others on trail

Question
I have had horses off and on for 20 years- am 45 years old.  My horse in the last year(have had him for 2 years) has started to pin his ears back and try to bite any horse that comes near him on a trail, including his pasture buddies (he does not do this in the pasture).  I have tried turning him away from other horses when he does this, turning him around, backing him up, all to no avail.  Also have tried tapping him on the neck with a crop when he does it, but that does not work either.  He does this whether leading the group or at the rear.  What do you think is causing this and how can we fix it?  It makes the ride unpleasant for others having to look out for his biting.

Answer
I would say he is either protecting you and does not want other horses by you or playing and ignore you.  either way, you need to be more aware and do something before he does it.

so when you know he is about to do, redirect his attention, make him flex, tuck his head, don't hit him with crop.

I would tie him more with other horses, so he learns to stand and be around other horses, horses need stand time and it teaches them patience, lots of people only tie to saddle up, tie him with other horses while you clean stalls, do chores.

Bottom line you have to start stopping this before he reaches out.  Lots of horses do this, so it is not a huge thing just annoying to you, so use it as a training opportunity, move him in closer, move him sideways, ride him just ahead, back him just behind, every time he is about to do you have to him thinking you know what he going to do and it causes him work. The spinning and turning sounds like it is being used as punishment not as training.  Work him calmly for this and don't try and punish him for it.

Rick