Lately you have published several letters concerning flag etiquette. I, too, have become somewhat obsessive about something I just verified for myself concerning the placement of an American flag on a uniform sleeve, or a moving object such as a truck or an airplane.
The field of blue should be on the left only when appearing on the left shoulder or as observed on the left (driver's side) of a vehicle.
When applied to the right shoulder or side of a vehicle the field of blue should be on the right to symbolize the blue field leading the way as into battle or leading a parade.
It's true -- look it up. I see so many violations of this regulation on police and firefighters and also Boy Scout uniforms. It's all I can do to restrain myself from saying something inconsiderate and being told to mind my own business.
Thank you for giving me this forum.