Can someone explain why the flags do move as astronauts pass them?
The speculation of a breeze from the astronaut causing the flag to move can be dismissed by an observation of the time that the flag is not moving. Including when the astronaut by the pole is bouncing around and then walks away, which caused no flag motion at all. There are plenty of videos that show the various flags for extended periods with absolutely no movement, something that would not be possible in an air filled environment.
BTW, you have question outstanding from the past few days in the JFK thread, why are you raising new questions in a thread where you have been absent for a month?
edited for spelling