This little guy is pretty remarkable: a fixed-wing aerial drone that lands by clinging vertically to a wall, and takes off from the same position. I'm not saying this is the future of spy planes - but it should be.
The Perching Project comes from the Biomimetics and Dexterous Manipulation Lab at Stanford University, and uses small spines to attach itself to rough surfaces. The drone approaches the wall at speeds of up to 35km/h. As it nears contact, it sharply cuts its speed down to 11km/h, tilting its body upwards so that landing legs can grab hold. And if you think the effect is impressive now, get a load of its creator's ultimate vision:
A flock of small, unmanned air vehicles flies quietly into a city, manoeuvring among the buildings. They communicate as they search for places to land, not on streets or flat rooftops but on the sides of buildings and under the eaves, where they can cling, bat or insect-like, in safety and obscurity... The fliers stay attached for hours or days, consuming little power and emitting no sound as they monitor the area. When finished, they launch themselves with a jump and become airborne again, ready for their next mission.