Both The President and First Lady have many people fly with them on their travels. More than likely Barron departed the plane with the USSS or press of his grandparents Other people who are NOT filmed by media.
Could be..............
I think you are right HM.
After the way Barron has been bullied, I’m sure Trump has given orders to not even film him, I hope that is the case anyway.
Leave this young boy alone.