I once took a filmmaking class from Robert Mehnert who directed a documentary about the SR-71 at a time when its production was at risk of being discontinued. At first only a few hundred people in Congress saw it, but based on the size of the order for new planes, he called the highest-grossing opening weekend of all time. (I haven't been able to find the film online anywhere.)
I tried too, but since the documentary is simply called "SR-71 Blackbird", it makes it hard. The subtitle "To keep the peace they fly alone... unarmed... into the unknown" ist cool but yields one result: an auction of the movie poster [0]
In turn, the movie poster however let me to a reverence to the movie in the book "SR-71 revealed the inside story" by Richard H. Graham, Col. USAF (Ret).