Go here: http://www.x10.com/products/x10_vk45a.htm
Just one idea but shows relative costs.
What I do for aerial images is use a video pencil camera attached to the view finder, thus I see what the camera sees.
But I'm not about to set the $5K camera anywhere near a target (there's aways that chance).
There are about as many ways to skin this cat are there are people who want to do the skinning.
Just google on wireless camera, and have fun.