My employer company users lasers, the largest of which is rated at 150 Watts, in its products and we operate a laser test range in KonTum Province in VietNam. Our range, several kilometres in length, at 5,000 feet, is used to develop military applications.
Most of the lasers used to 'flash' aircraft are rated at less than 0.5 Watt. Human eyes are more sensitive to green lasers as opposed to red lasers. Furthermore, the laser optics cannot be focused at greater than around 500 feet given the poor quality of the lenses.
What is described as 'burned' is impossible even at a couple of thousand feet. The complaints are based more on the bodies reaction, in other words a psychological reaction rather than a physiological reaction. I have been at the 'hot' end of a 150W laser, 1 kilometre distant, and suffered no injuries.
Back in the 1960s there was an experiment at Hamilton Airport , Ontario (IATA Code: YHM, ICAO Code: CYHM) using high powered gas lasers to drive birds from runways. It failed, although we did enjoy many chicken and turkey dinners!