I do not believe a judge currently has to authorize someone's placement on the No Fly List, which right away raises red flags. So the No Fly List is definitely unconstitutional as it is currently implemented, but I wonder if it would be replaced a constitutional implementation. For instance, if FBI, CIA, or NSA had to clear a probable cause legal hurdle in order to place someone on the list, and if a judge, rather than the TSA, had to approve their placement, then the program might be constitutional. The proceedings might have to be secret, so the no fly list would function like some NSA programs that I know folks here are so fond of (note: sarcasm) - but at least it would involve the judiciary rather than giving the executive branch carte blanche to prohibit anyone it deems suspect from travelling.
I'm pretty sure such a constitutional implementation already exists: namely, they can just revoke your passport, which I think has to go through due process.
