Not sure if he meant flying OUT 1,500 feet as opposed to 1,500 feet above ground. At 1,500 feet above ground, it's pretty hard to follow a golfer with a 20mm equivalent lens, let alone a golf ball. You make good points about knowing about all potential aircraft flying in or nearby the airspace you intend to occupy. However, anyone who seriously thinks that one of our 2.5 pound P3P's is going to take out another aircraft is being overly dramatic. Birds and ice chunks dropping off other aircraft are just as
unlikely to do major damage, but no one is banning birds from flying through their airspace, or limiting their altitude. It takes a whole flock of birds to take down an aircraft, and even that is a very rare occurence. The most likely scenario of drone v. airplane is drone is obliterated, just like a bird would be, and aiplane paint might be scratched. Anything else would be a freak accident requiring a perfect storm. There has never been one yet, despite all the hysteria created over this scenario. Avoid all occupied airspace, but if it happens, it will be like a mosquito being swatted. The flyswatter won't need replacing!

It would be like a bicyclist taking out a bus. In any collision between a bicyclist and a bus, the bus is always going to win. Crunch! Later, "Oh look, the paint is scratched."