The Air National Guard is very similar to the US Air Force reserve except the commander in chief is the governor of the state rather than the President - unless on federal orders.
Far from being the poor step children of a couple generations ago, the Air Guard is fairly well equipped. In 1990 the South Carolina Air National Guard was the second unit Air Force wide to field what was the latest block F-16 at the time. Several months later they were the first US fighters to land in Saudi Arabia after Saddam invaded Kuwait.
The Georgia Air Guard flew B-1s for quite a while.
MOST of the pilots in the Air Guard have jobs that allow them to fly missions during the week or on some flexible schedule. Lots of airline pilots, I think.
The national commander of the Air Guard makes the claim that the Air Guard and Reserves fly 40% of the USAF missions at 10% the cost. Although that seems to ignore the entire USAF infrastructure that is there 24/7 to support the reserve component mission, it's a reasonable effort to show how it fits.
I read recently that almost all of the USAF tanker missions are flown by Reservists.
From a green rather than blue perspective, much of the US Army's "reserve component" (Army Guard and Army Reserve) heavy equipment is in the Guard while support services are in the reserves. This allows governors access to heavy equipment in the event of emergencies/disasters in their state.
Back to the Air Guard - it is quite possible to join the Air Guard (Army as well) and go to flight school. Typically, these slots are limited and most members join the Guard or Reserves after completing a regular active duty tour.
The US has a far more robust reserve program than most countries. It includes prorated pay and prorated pension. Last month I transitioned to "US Army, retired" 32 years, four months, and 17 days after enlisting for Officer Candidate School. In the 29 years between enlisting and transferring to the "Retired Reserve" I accumulated 13-1/2 years of full-time active duty equivalent - hardly the "weekend a month and two weeks a year" many people assume.