But do the planes before the cold war have a motherloving 30 MM GATLING GUN?
P39 Aircobra

37mm cannon
ME-262

4 30mm autocannons

this one has a 50mm autocannon
All of these planes are pre-cold war. Armed with fancy spinning barrel gun? No, same or large caliber? Yes.
Now as for the cold-war era A-10. It was designed a dedicated close air support aircraft for the USAF. In a shooting war between the Warsaw PACT and NATO most of the A-10's would have been shot down within a week. What really makes it a tank killer is not the 30mm gun, but the Guided Mavericks and Rockeye II cluster bombs. That 30mm gun is a peashooter against modern armor, however it would have devastating
to older tanks such as the T-55, light vehicles such as trucks, and lesser vehicles such as BMPs.
Warsaw PACT on the other hand was more than prepared for NATO airpower.
RADAR based systems(flares are useless here)
Meet the 9K33 Osa(SA-8 Gecko)

It is mounted to an amphibious TEL and can hit targets out to 12 meters. Carries 6 missiles with a 15km range Widely exported.
2K12 Kub(SA-6 Gainful)

Tracked TEL, 20KM missile, widely exported
9K37 Buk(SA-11 Gadfly/SA-17 Grizzly)

Upgrade to the KUB. Tracked TEL, has about a 38 KM range
ZSU-23-4 Shilka/Biryusa

SPAAG, four radar-guided 23mm autocannons. Widely exported.
9K22 Tunguska

Spaag, two twin radar guided 30mm autocannons and 8 Radio command Missiles with 8km range.
9K330 Tor

8 Missiles 20Km range, OSA replacement
Infared
Strela-10M

4 missiles loaded, IR guided 5km range. Additional rockets are stowed in the hull. Widely exported.