I'm sure no-one has ever thought about all these issues.
How do you lay a smokescreen if you are in a plane? The smoke will end up behind you.
Maybe you could use smokebombs or smoke rockets or something? Ahh, exactly the sort of things that this weapon would be designed to counter.
And as for mirroring, perhaps you should think for a little bit about how you'd make a smooth, spotless mirrored surface over the whole of a aircraft. Including the engine exhausts. I don't imagine for one moment that this would be easy to do with an artillery round or mortar bomb either, given the stresses inflicted on them by firing, and that's even before we start worrying about making some kind of ultra reflective, super insulating laser armour which is yet still compact and lightweight.
Sure, lasers won't be terribly useful against ground vehicles (easier to armour, smokescreens etc), but if you read the article that was never the intention of the system anyway.
And whilst i'm ranting, you won't find x-ray lasers out of the lab (though people have though about it... see the good old SDI) but UV lasers do exist, in the near ultraviolet range at least.