@DoiugWright - There was never a separate color for Air Scouts or Air Explorers. So, they would wear a red backing with their service star. That backing covers all youth participation in programs for older youth.
Siilarly, those who were Senior Scouts in an outfit between 1946 and 1949, would wear a red backing with their service star.
Senior Scout outfits were created to allow an older-boy unit to be created without choosing a specialization, i.e. Sea Scouting, Air Scouting or Exploring. Within the outfit, individual Scouts could choose the program in which they wanted to participate. A large Senior Scout outfil might have an Air Scout crew, a Sea Scout crew and an Explorer crew. Boy cou;d readily shift from one older-Scout program to another within an outfit without the need to register in another unit.
The primary youth leader of an outfit was called the outfit guide. The unit leader was called an outfit Advisor. Senior Scout outfits choose one of two uniforming options. They could have all their members wear the same uniform or allow their Scouts to wear the uniform representing the program in which they were participating.
In 1949, all Sentior Scout outfits had to choose whether to become an Explorer post, a Sea Explorer ship or an Air Explorer squadron.
Senior Scouts who were in outfits are different from Senior Scout who were in troops. Starting in 1935, boys were considered Senior Scouts wnen they turned 15. They remained as members of their Boy Scout troop. Air Scout, Sea Scout and Explorer Scout advancement was available to Senior Scouts in troops. In fact, during this era, the type of unit in which a Scout was registered didn’t matter. Any boy who was at least 15 in a troop, ship, post or squadron could earn any older Scout advancment.
When Senior Scout outfits were created in 1946, the option for older booys to participate in Senior Scouting programs within a Boy Scout troop was eliminated. The troop could simply charter an outfit, and the older boys could be registered in both the troop and the outfit, if they wanted to continue offering the senior programs.
Those who were Senior Scouts in troops shoud wear green backings on their service stars, since they were registered as Boy Scouts at the time.
When the entire older-boy program was reorganized in 1949, all Boy Scouts were now considered Explorers when they turned 14. The Explorer advancement program was available to these boys within a troop. Troops running this program could have both a Scoutmaster and an Explorer Advisor. The older boys typically wore an Explorer, not a Boy Scout, uniform. Explorers in troops could not work on Air Explorer or Sea Explorer advancement. They had to join a squadron or ship to do so. Exploring in troops ended in 1959, when the separate Explorer advancement program was eliminated.
Those who were Explorers in troops were Boy Scouts participating in Exploring. Their service should be recognized with a service star with a green backing.