If you right-click your route map, (at least in Firefox, it doesn't completely work in IE because the URL would exceed its maximum length), you'll find the URL to the Great Circle Mapper. In the end, it says 'PATH=' and then come the airport codes. Select them, copy and paste, and you're done! I don't know if it would show all routes, but it shows a lot of them much faster then I could ever type them.