Do you mean they might see it on radar?
Obviously you should comply with all regulations, but a rocket like that might not be all that visible to radar at all.
I presume it has no radar transponder of any kind so it would have to be detected by primary radar. This is in itself perfectly feasible if someone is actually looking for things that are not supposed to be there (enemy aircraft and such), but otherwise not that likely.
Most air traffic controls actually depend on secondary radar (i.e. an active transponder on the aircraft).
On primary radar your rocket will probably not look all that interesting: it only flies for a short amount of time and doesn't have a big radar signature. Since a rocket is essentially tube-shaped it will reflect some radar energy but not very much. Airplanes typically have structures (such as the tail rudder or wing attachement to the fuselage) on them that make them into retroreflectors producing strong reflections.
You will find that such convenient 90 degree reflectors are avoided on all stealth aircraft, although those have further design improvements and radar absorbing coating your rocket does not have. Perhaps they'll wonder if a ostrich has finally be able to fly from the raw data