Flighty does mean 'can fly'. It also tends to be used to mean they startle easy, squawk and flap like mad if you try to corner them to pick them up, and are just generally noisy and skittish. A lot of this will depend on their breeding, so you could get calmer ones or flightier ones depending on how selectively they've been bred and what strain they are. But in general I would say it's true of Leghorns. Light mediterannean breeds all tend to be 'flighty' just cause they're lighter and therefore more able to fly. My Leghorns were very noisy when I first got them but once they settled in (a couple of weeks) they are now no more noisy than my other birds. They are every bit as nosy and friendly as my other birds when it comes to following me around and coming up to me for treats, but they don't like being picked up and will continue to screech and struggle long after my other birds would have submitted and calmed down. Also they can fly but don't tend to do so any more than my other birds, who will all manage to crest a 6' fence if they really want to, well, all apart from my fat Cuckoo Marans who can barely get a foot off the ground...
