According to the package info, this light is not a threat physically to the eye at a distance of at least 10' and that's aimed directly into the eye. The Pilot more than likely will only see a point of light along that line, no more than from a bright red blub. This would most likely be a flickering/blinking light. Once the plane acknowledged (by maneuvers) that he saw the signal,I would presume it would stop. I am not familiar with any legal restrictions regarding a unit used as such. Good question, thanks.