For more detail on how effective Skunkworks was, read Kelly Johnson's book. It was recommended to me by a buddy at JPL and it's a wonderful view into how they did things on time and below budget on projects like the SR71.

Not an affiliate link: https://www.amazon.com/Kelly-More-Than-Share-All/dp/08747449...

That's a great read. There's also "Kelly":

https://www.amazon.com/Kelly-More-Than-Share-All/dp/08747449...

This article mentions Clarence "Kelly" Johnson. If you don't know who he is and care to learn more about one of the best engineers that ever lived (SR-71 is his work), check out his book: https://www.amazon.com/Kelly-More-Than-Share-All/dp/08747449...

His second in command at Lockheed, a man named Ben Rich also wrote a very good book: https://www.amazon.com/Skunk-Works-Personal-Memoir-Lockheed/...

That book is by Johnson's protege and successor, this one is by Kelly himself:

http://www.amazon.com/Kelly-More-Than-Share-All/dp/087474491...

Both are amazing stories.