I think that this man's concerns are unfounded. Really, if aliens are visiting Earth, then they are doing their very best to keep it a secret. Which probably means one of two possibilities:
1. They are planning a suprise invasion, and our attempt to shoot down UFO's are justified.
2. They are peaceful aliens who are complying with a noninterference directive, and therefore will not attack us no matter what we do.
Really, you would think that they would expect to be attacked whenever they overfly the US and fail to follow a flight plan. It should be evident even from space that there are hundreds of competing nation-states that hate and fear each other. What are they expecting when they land? Milk and cookies?