Table Tennis Theory

Why can you play table tennis while travelling on a train without the ball flying back when it has left table?
Should the table tennis ball not fly to the back of the train after it leaves the table, also, does a fly trapped in your car have to fly along at the speed your car is going in order to stay airbone insied teh car? whay physics theory explains this
So long as the train is moving in a straight line at a constant speed, the game won’t be any different than it would be if the train were stopped. This is a consequence of both Newton’s and Einstein’s mechanics. The train, whether moving or stopped with respect to the ground, provides an inertial reference frame in which all the laws of physics are as valid as in any other frame.
