He apparently wasn't on it! Yeah, the Republicans wouldn't forbid people on the no fly list to have guns. Guess who was NOT on the no fly list? But he was on the Terrorist watch list? It would be funny if it weren't so sad.
http://www.bbc.com/news/world-us-canada-36545432
The FBI has two terror "watch lists". The smaller one bans flying to and from the US and there is also a larger one, which Mateen was on.
Mateen was put on that list for 10 months while under investigation following inflammatory comments at work.
But the FBI concluded there was no evidence he was a terror threat.