I think it would look cool as hell, but can think of a few reasons solid or liquid fueled rockets could be very dangerous. For instance some guy is working on his plane in the pits & you hear the dreaded "oh *****"...you hope he inadvertently hit the gear switch (which we all know happens & is currently about the worst switch you can make a mistake with)...but then you see a small dot & a smoke trail comming straight for you. Or a rocket is fired from a jet that the owner didn't realize the down angle at the wing tips due to washout & into the spectators it goes.
Do I think I & the gentleman that started this post can probably safely pull it off ?...YES.
Do I think everyone in this hobby around the country with a turbine waiver can do it for a year straight without incidents ?...damn sure wouldn't bet on it !!!!
Jay