We like to travel someone on the plane with the horses on the longer trips (ie NZ or North America) for that very reason... nothing personal (indeed all my experiences with companies that fly horses have been absolutely fantastic). I just feel a horse will be best cared for by the owners themselves. Ours get their legs bandaged (it actually took quite a bit of convincing for me to be allowed to leave them on on a Canadian flight hehehe!), given a mild tranquilser if time permits (ie some domestic flights close to the race it is impossible to do so for withdrawal reasons) and get ear plugs put in. I also feel that when they travel with someone they know, they travel better too