Aeroplane windscreens are pretty resilient. I can imagine, maybe, a windscreen cracking but not breaking. On take-off, it may result in a decision to burn off excess fuel and then return to stand to avoid a potential depressurisation later in the flight and, of course, on landing could result in a delay or cancellation to the outbound flight the aeroplane is expected to fly.

There is also the potential to wreak havoc with overhead power lines, or telephone cables, as well as invading privacy (overflying a "drone" over someone's garden to spy on teenage daughter sunbathing, or wife having a shower for example.)

It seems as if we need some sort of legislation about the use of these "big boys' toys" in the proximity of airports and around tall structures such as High Tension Power Lines, as well as protecting peoples' privacy.