"Aircraft" is always pushed around with such vehicles, but "missile" (...demonstrator) or "weapons carrier" might be closer to the most feasible and/or intended functions (which follow the form, and vice versa)

PS. A missile which is possibly not so easily noticed and intercepted as ICBMs, or without the need to have a launcher placed in the theatre (or bomber carrier getting nearby) as cruise missiles; how convenient. The good old search for tech which can destabilize the balance and trigger a new arms r