help with poor trailerer

["Beckstrom, Carolyn" <Carolyn.Beckstrom@standardregister.com>]

If anyone has some insight or experience with a horse who is nervous/unhappy
while trailering  could you please let me know how you were able to solve
the problem.  My horse is 7 years old, I've had him 3.  My trailer is a 2
horse straightload bumperpull walkthrough that is 7"6" high, 3' stall width,
he has plenty of headroom and about 1.5 feet behind him when his chest is at
the chestbar.  I don't think he is claustrophobic, but it's possible.  He
just hates to stand still.  He is very antsy, but basically very sane.  He
has always pawed and stamped some while trailering, but has been getting
worse this year, and now that I have been trailering alone, he is
unbearable.  He smashes at the floor and hits the escape door with his shoe,
he rocks back and forth and twists his haybag till it is a tight ball up
near the ceiling.  He has been getting off the trailer drenched in sweat.
Last weekend he banged around all but about 5 minutes of our 45 minute trip
in both directions.  I am afraid that he is either going to hurt himself,
exhaust himself, damage the trailer, or get himself so freaked out that he
will never load again.  I would like to take him to rides that are 3-4 hours
from home, but I am afraid to do it while he is acting like this. (I have
taken him this far with his buddy and he will still bang around even after a
long trip so I know he's not going to just get over it after an hour or so,
he's just much worse alone)  He will load no problem, but will start banging
almost immediately.  There is no difference if he is on the highway or
backroads so I don't think it is the noise or speed that bother him.  he is
definitely anxious in there, especially without a buddy, but he is also a
pretty excitable horse and can work himself up into a fit.  I ride him alone
often and he is fine.  Does anyone have any ideas?  Do I just let him smash
around?  should I do small trips and pray he gets over it?  what about a
livestock trailer or a reverse slant-load?  Is it hopeless?  I appreciate
any advice and feedback you can offer.  Or any books that have been helpful.
Thank-you
Carolyn and Gem in MA