Trump gets it. Sure, if someone gets on the no fly or terrorist list, they may be a danger and not get to buy a gun or fly BUT each list must have an appeal process as a person mistakenly or wrongly on the list should be able to get off the list. The is another fundamental right - due process. The individual learns about the listing when flying or gun sale is denied, as being put on is not disclosed to the person.
The current no-fly/terror watch list is kind’a like Animal House’s “double secret probation” since you don’t know if you’re on it!