a paper airplane might do quite nicely... low budget, quick and easy to assemble, aerodynamic
hi, i'm a UTS engineering student, and went to Penrith High School, we recently had a project of building a wind powered car that moved into the wind source, and had to carry a load. and it was the best ratio of weight vs. time over 2m that would win.. we came second.
although our design was semi complex, we had to think of the most efficient way of transfering the wind from the fan, through our turbine, and into forward motion, while keeping a thought on aerodynamics so the vehicle didn't get pushed back by the wind.
what you need to think about in your design is how much lift you can get, cause 10 metres can be a long way for a small craft.
if you have a large piece of foam handy, you could carve out a glider, make a large wingspan, make sure the wings are shaped correctly, and it should work.
i hope i've been of some help
edit: something like this
http://www.guillow.com/GuillowDetail.asp?UID=1603617&prod=2645-1&SeriesId=15&FamilyId=3
but build it yourself
the foam will give it some weight so it there's any wind it shouldn't get blown around either, so just give it a big throw into the air
