Here is a closeup of the mount I made for the flag. It consists of two steel brackets. One attaches with two bolts to the two sides of the luggage rack. The other bracket mounts with one bolt through the top of the sissy bar. Both brackets are removable in 5 minutes if I am not using the flag.
The flag itself is removable from the brackets with one thumbscrew (shown at the base of the aluminum pole) so I can use the flag when standing in a flag line. Two pieces of aluminum tubing telescope one inside the other for the staff. When extended, they make a flagpole almost 8 ft high.