He bought his airline tix with cash, didn't go through US TSA clearance, and didn't show a passport at the Czech border? You cannot get from NYC to Prague without leaving a paper trail.
But his cellphone pinged a cell tower in Prague, according to "intelligence sources."
This is utter BS from lying reporters. Or more likely, their sources were Brennan, Clapper, Comey… all known treasonous liars.