I've always just tied the best windsor knot I can make and kept it tied. When I need it off, I just slide the small part (like a zipper tie) and took it off from around my neck. Unless you're head is giant, then it won't work.
That's what I do, too. It's hard getting that knot just right, and when it is, I like to keep it that way. Every once in awhile, I get a compliment on my knot cleavage and it feels good
To all the nay-sayers. I'd happily fly sans tie. As long as it's required, however, I'll be fishing for that cleavage compliment and doing it right LoL