I'm not sure about the Union Jack, but the US Flag does not need to be displayed "in reverse" on the right side of vehicles or uniforms, according to the US Flag Code. It generally is in US Army Uniforms and USAF & other aircraft to give the impression of the flag streaming backwards was the vehicle moves forward; however, it is not displayed this way on the Boy Scout uniforms or the uniform of the Madison County (NY) Sheriffs Department. Now, that being said, I do agree with you that the reverse flag on the right side of a vehicle does look better; and I would prefer that model companies provided it on their decal sheets if the flag is provided.