It is based loosely on a true story but with a lot of Hollywood license taken. I saw it when it first came out and it is one of the few movies where everyone left after it was over without saying a word. It was like attending a wake.
Seems I read it was based on the true story and the earlier film. Not something my wife would want to watch but a bunch of us guys watched it on a golf outing.

Not to get off topic buy my wife and I just watched "Bridge of Spies" and it is an excellent movie based on the Gary Powers U2 incident in the 60s'. Tom Hanks does an excellent job as the lawyer that negotiated the spy exchange. No F bombs are slut, just a good movie.