I love aviation, and the SR-71 is one of its pinnacles in several aspects. The Wikipedia article might not represent them all, but it hits the facts pretty well. In my opinion, this is valid history. It may not be great history, but it is valid at least. Crowdsourcing of the article can be good and bad, but I think most people are reasonable enough to keep it good. It can be easily vandalized, but more often than not someone is ready to make a correction to the page to remove it.
Wikipedia’s terms of service are in some ways the best and worst parts of the site. They make it easy to edit articles and create new ones, and they make their information as open as possible. They also limit the interpretation of topics quite a bit. I don’t think that’s a bad thing as their goal is to be the world’s greatest encyclopedia. Encyclopedias tend to remain neutral and stick to the facts. In this same vein, I think Wikipedia in general should never be cited as a source academically, with the exception of articles which are the only source for a topic. Just as you wouldn’t cite the Encyclopedia Britannica but rather the sources it cites, Wikipedia is a great research tool that needs to be used properly in an academic setting.