Miles M93B experimental aircraft
Lockheed XFV- Designed to take off and land vertically onto its tail. Designed for use on aircraft carriers.
Mcdonnel XF-85 Goblin- Designed amazingly to be diploid from the bomb bay of a bomber.
Nasa X29
The Russian K7 concept- This is an exaggeration of a mythical aircraft from the 1930's.
The Mil V-12- The Largest Helicopter in the world
Vought V 173
All of these planes come from a time of aeronautical engineering when we were still trying to fined the optimum design for flight,thus anyone of these mad ideas could have been the next big break through.
http://en.wikipedia.org/wiki/Messerschmitt_Me_323
http://en.wikipedia.org/wiki/Bartini_Beriev_VVA-14
http://en.wikipedia.org/wiki/Miles_M.39B_Libellula
http://www.gizmodo.com.au/2013/01/25-bizarre-aircraft-that-dont-look-like-they-should-fly/
http://www.hoax-slayer.com/russian-K7-heavy-bomber.shtml
http://www.candiler.com.tr/mil-v-12/#!prettyPhoto