Our friend's 11-year old son caught me playing Simpleplanes over this year's Christmas dinner cometogether.... In the end, he ended up building this plane which I tweaked the flying characteristics a bit.

The plane is built completely out of standard blocks. Takeoff speed is about 170 mph, top speed 450. The center of gravity is pretty far up front so the plane needs about 1/4 trim to fly straight without touching the controls. It has neither flaps nor air brakes so landing approach is pretty fast but landing itself is surprisingly smooth. Just keep the nose up until the rear wheels touch the ground.. that's all.

Also check out Travis' Jet Thunderbolt that can do 700 mph and still use mostly standard building blocks