Actually I do not think PDR1 proved you could not hit an aircraft. I think Chesty's point about divergence (beam diameter at height) easily found on the internet confirms what most of the professional pilots on this site know; that it is not that difficult to target an aircraft. If you can hold it steady enough to point at a star then hitting an aircraft is perfectly possible. Where I thought his calculations were interesting was at what distance he thought it would damage your eyes. The 900 mW laser site sells safety glasses so obviously close in the manufacturer thinks this is a problem. About ninety percent of my encounters with lasers have been on approach. One airfield I regularly approach without lights and with autopilot to minimums because it is such a regular event, not in Europe I might add and nothing gets done about it despite regular reports.