Lots and lots of aeroplanes (there, i used the English terminology) from WW2 and before, including a couple used in the movie Those Magnificent Men In Their Flying Machines. Here's the aptly named Bristol Boxkite:
The cool think about Shutttleworth is that everything works and flies. Well, with one notable death-trap exception. Rumor has it that the Boxkite gets to fly only in perfect weather with winds under 2 mph.
Very cool place.
Update: Added a few pictures in a photo album (see right)