well, if my dog was badly behaved and had a habit of running away from me, I'd think twice about letting her out on a leash, but since I've never had that problem with her, I don't think I'll have an issue if I walk her on a leash while I'm in the airport, especially if I take her outside to do her business when I get off the plane. It'll be her first time around so many people, though, so she's likely to stick close to me, even if she does manage to get off the leash.