Trump's an idiot. Last time he blocked Bombardier sales he caught the C-Series at a critical time with first sales getting confirmed and the beginning of positive cashflow. When that happened it completely destroyed the program and forced us to give it to Airbus for free so we could do the final assembly in the US and avoid tariffs.
This time it barely means anything. These business jets get sold to millionaires and billionaires who likely register them offshore anyways to avoid taxes. You can just fly that jet in the US regardless of where it's owned or registered.
He's just doing his old trick again but doesn't even understand why it worked in the first place.