writes in with an interesting look at some aircraft that should have stayed on the ground. "It's more than 110 years since mankind first took to the air in a powered aircraft. During that time, certain designs have become lauded for their far-sighted strengths – the Supermarine Spitfire; Douglas DC-3 Dakota; or the Anglo-French Concorde supersonic airliner, to name a few. But then there are planes like the Christmas Bullet. Designed by Dr William Whitney Christmas, who was described by one aviation historian as the 'greatest charlatan to ever see his name associated with an airplane', this 'revolutionary' prototype biplane fighter had no struts supporting the wings; instead, they were supposed to flap like a bird's. Both prototypes were destroyed during their first flights – basically, because Christmas's 'breakthrough' design was so incapable of flight that the wings would twist off the airframe at the first opportunity. Just as many of the world's most enduring designs share certain characteristics, the history of aviation is littered with disappointing designs."