You may be right about automatic inclusion on the no-fly list and you may not. I admit that I don’t know the criteria that are used to put people on it.
I would say that if it there are reasonable grounds to believe that people are such a material terrorist threat that they should not be allowed to even ride on a commercial airplane that that is probably reasonable to also not allow them to have a firearm in the same way that a convicted felon or a seriously mentally ill person is not allowed to own a firearm.
In the end, it’s all a balancing test.
You have the right to freedom of religion, unless your religion says that you can have multiple wives, in which case you don’t.
You have the right of freedom of speech, unless your speech is defamatory, in which case you don’t.
You have the right of freedom of the press, unless you’re printing child porn, in which case you don’t.
It’s all about reasonable vs. unreasonable restrictions balanced against a material public interest. It’s never black and white. Nothing in the Bill of Rights is absolute, for example, you have no Constitutional right to own a fully-automatic firearm.