I am sure as this progresses I will work from more and more from my own photos but it is fairly hard to go back and shoot historic moments and many of the shots I use are promotional photos are for all intent and purposes in the public domain. They are disseminated to promote the brand and not as an object of work unto themselves.
I think I have a decent argument that I am in fact creating new intellectual property because I am adding details that are not discernible in the photographs. There is a surprising amount of checking and cross referencing that goes on with each image. I usually don't do stuff with only one angle, I want two or three because the tiny logo on the rear quarter panel in the photo is a pixelated mess and I have to draw it precisely because you cant blur vector lines. So there is a lot that I add to the thing to make it what it is. If I used a program to convert the base image to a piece of automated art then I could see the argument but that is not the case.
Also as part of the process I have to re-create all of the logos and lettering which can be more time consuming than actually drawing the cars. After having owned an advertising agency I get into corporate identity as much as the making of the car. Each car is a moment in technology and advertising that then transcends into art and history if the performance is good enough. It is a nexus of public performance and in that sense the resulting exterior of the car is made to be consumed by as many as will see it, so my work is more along the lines of Warhol's Campbell's soup cans.
Anyway I have spent far more money to get here than I have made or will make. I do this because I like to do it not because I think I might make money at it. I set up the t-shirts because I wanted a t-shirt and I made a calendar because I wanted a calendar.