How to find the ISBN from the DOI?
Articles don't usually have an ISBN since they are for books. It should be sufficient to give the title of the article you are interested in to copyright.com, which is AIAA's preferred mechanism for copyright license clearance. That being said, searching your article's title on copyright.com gives a null result. As such, you should probably contact AIAA directly, or stick a sequence of zeros into copyright.com's extended request form.