It's funny how UK stands out as a place where they try to kill him. There were rumours he canceled his UK trip last year due to having knowledge of assassination plot. Now that he does visit there, immediately someone tries to kill him. There was sniper team guarding POTUS at the golf club but they made a crucial decision not to kill the paraglider guy which was a huge mistake in my opinion.
It's also possible POTUS was not the actual target but they just wanted to send a message that they can get to him easily and proved it by sending one of their useful idiots in there and killing a nearby SS agent.