Maybe this doesn't quite answer the question but I had an interesting observation a few years ago.
It was a clear, crisp, mid-winter Saturday morning in Toronto and I was out walking the dog. I heard aircraft overhead and looked up to see 2 aircraft in formation at about 800 ft. One was a King Air, probably a 200, the other was a Lear 55. The King Air was closely following just behind and above the 55. They continued on over the city and eventually disappeared. Both had "N" registration as opposed to "CF" or "CG". I can only guess that the King Air was photographing the Lear. Bombardier has a large plant in Toronto.