That's a good question. I'm working on a project right now taking screen shots from TV and extracting data. It's sort of working. <smile>
I think much of this would depend on picture quality and placement of the tail numbers. Software would need to be developed around tesseract to know where to look for the numbers in the picture that was taken of the aircraft tail.
The toll roads around me take pictures of license plates while vehicles are going 75 mph and are pretty accurate. I wonder what they are using?