I said the same thing when I first had the link forwarded to me, but watch the video. The U2 spy plane serves a very important role for the airforce, but can't land or take off on its own.
This is a great example of designing something with an extreme focus on achieving its purpose while ensuring any necessary, but non-core functions are only minimally included.
"""My favorite video on bootstrapping/minimum viable product:
http://www.youtube.com/watch?v=Zv17lF60OHY
It's well worth watching the whole thing."""