I think the question to ask is if USA has the right to fly a drone over Iranian territory. Besides, its only a drone that was dropped by Iran, in 80s America shut down an Iranian aircraft with 190 people or so on board.
I think Trump should trend with caution, already, Arabs are flooding every European country in the name of migrant because of problem created by past American president. Those immigrant will cause more problem in the future than what we are currently facing worldwide. So, president Trump should not add more migrant to already on ground.