They could use it for more perminant fixtures, things like semi-portable "parking spots" for heavy artillary, or airplanes, or bunkers; things like that.

But yea, for real use - it's not quite feasable.

Your idea for see-through airplane cockpits would be awesome, that way they could see onto the ground in front of them to make sure they aren't going to run someone over. It'd be like a added security measure, so they dont just rely on a flagger.

My question is though, wouldn't it just be cheaper/easier to use a camera? LOL.