Since I fly RC Jets, Heli's, Giant scale and do almost everything RC Ill comment. Jets can be had for less than $1000 for an airframe, and can go up to that $15,000, which is an extreme high number for a kit, if there are any.. A buddy has one that has been shown to break 230mph on the onboard speed sensor, and this jet has been known to do up to 275MPH. Not bad!
Also, FWIW, we radared my STOCK heli and it did 61mph, and we did my 40% aircraft and it did 82 with a headwind!
Here is a vid of a few of us flying, 3 different jets, the F-15 is mine

and one 40% plane doing some 3D stuff.
The F15 airframe is already built and painted and can be had for $1700, the engine puts out 18lbs of thrust and costs $3200, then you need a bunch of extra's and radio gear, so its about $7000 in the air.
THE VIDEO