I want to make an observation on the 'flighty' comments about Arabians, not in a negative way, but more in a ......What if kind of way. These horses were bred to be war horses and to take care of their humans. They originally lived in a tent with their bedouin owners and had kids crawling all over them and were expected to tolerate and babysit the kids too. Because it was their job to take care of their humans, these horses are EXTREMELY aware of their surroundings and anything going on in their area. Because of their extreme intelligence, I think HYPER VIGILANT is a better word to describe what appears to be flightiness, but that word implies brainless-ness to me so I don't care for it.
Hyper vigilance though, that I'd sure agree with. The see and hear EVERYTHING and they are ready to run on a seconds notice. But think about how that could save your life in battle. If your horse heard the arrow, knife, bowshot, gun, cannon, long before you did and got you right out of there, you'd run to live another day. If your horse heard the panther, lion, tiger, snake, other nasty critter, coming in the tent and gave the alarm before you had any idea there was something out there, then how grateful would you be?
One thing you'll notice if you ever fall off your horse is, he'll most likely stay with you. I've never had an Arab run all the way home with an empty saddle. They might run 25-50 feet after you scare them silly by falling off, but they come back and stick around til you're back up and ready to ride again. Or to walk them home from the ground if you can't get back up. One day I used a 5 gallon paint bucket as a mounting block (yes, I am now fully aware of JUST how dim that was) and it tipped over and dumped me on my butt. My mare was so upset that she ran up and down the rail of the arena hollering and yelling to get someone's attention. Fortunately, she didn't! I got back up and got on from the ground and off we went, but she was very upset when I got dumped and was totally looking for help.