In the UK, the Royal Auxiliary Air Force did the same job prewar, and after it till 1957.
Its Pilots were committed to two hours ground instruction on a weekday; they flew on Saturdays and Sundays, and attended a two-week "Annual Summer Camp" alongside Regular Squadrons.
They flew the FJs of the day (Meteor and Vampire). There were 22 Squadrons of them (one third of our FJ force); they were reckoned as efficient as a Regular Squadron and got much the same number of hours per month.
They gave outstanding service in the Battle of Britain (many of our top-scoring aces were Auxiliaries); they wore regular uniform (officers wore a little brass "A"s on the lapel, airmen a sewn "A" below the eagle on the sleeve); they were paid as Regulars; of course in my time most of the members were ex-wartime pilots, but National Service pilots were coming in in numbers at the end.
Why were they disbanded ? I reckon the Treasury couldn't afford to kit them out with Hunter or Swift (and most of their pilots were getting a bit long in the tooth).
Danny42C.