If you've ever wondered what happens when aircraft designers break all the rules, these five pages are for you. We've gathered some of aviation's most daring experiments—from the disc-shaped Northrop XP-79 to the pint-sized McDonnell XF-85 Goblin and the revolutionary vertical-takeoff Harrier—each one representing a bold "what if" moment in flight history. Grab your pencils and color your way through the machines that proved sometimes the most unconventional ideas lead to the most fascinating designs.
