Tactical Surprise: (most likely)
After a period of deteriorating relations between the Soviets and NATO, a political crisis develops that leads to the Soviets turning to a "false flag" operation on the high seas (or an assassination) that blows up spectacularly in their faces, leaving them with no option but to blame the US, Germany, or [insert NATO country name here]. Emotions run high, the Soviet People are outraged at the "perfidious actions of the West" (more than the Kremlin wants them to be, really, pushing the crisis even further beyond their control) all the way up to Cuban Missile Crisis levels. While conventional forces begin to mobilize, the absolute sense of approaching war is not taken critically by the West. However, as intelligence shows signs of a general mobilization of the Warsaw Pact, belatedly NATO orders its forces to mobilize.
Seeing NATO mobilization, the Kremlin panics, and orders a conventional pre-emptive strike into NATO territory. Soviet forces have a decent level of supply, good air strength, but much of their forces are out-of-position. They are up against a level of weak defense but deployed all along the frontier. Invasion of Denmark is possible, if not advisable. A mass air strike against NATO airfields will find a much smaller but fully ready and MORE capable [good luck with Mig-23s (1) and Mig-25s (2) against F-15s and even Phantoms] opponent. Air parity will soon establish itself, but with much of the forward NATO forces on their own for the time being.
It'l be a grind, that's for sure.
1) A good example of trying to do something that you're really not capable of, like the Mig-19. As opposed to the excellent Mig-17 and Mig-15 (thank you Nene engine).
2) Terrific for very high altitude high speed interception. If you're trying to shoot down B-70s, the aircraft it was designed to defeat. Not so much for air superiority combat. B-70s couldn't shoot back. F-15s could.
For air warfare, its a near thing, but with what we now know of Soviet capabilities in a tactical surprise scenario the Soviets will perform well (as their armies advance) at the start, before NATO airpower comes fully to the fore. The ability to fly across the Atlantic will represent the chance for the US and Canada to send its air forces forward logarithmically faster than in WWII. Long term, the Soviets run out of planes before NATO does. On the ground, its much more difficult to make a call. But I'd say that the Soviets, freed of some of the supply limitations of a Strategic Surprise, will have a better time of making a good fight, but with the truth of the deleterious effect of the black market (3) being what it was on the Soviet military back then, they may not have the ability to make their opening successes stick.
3) Frex, the downing of that South Korean Flight KAL 007 was because the Soviets thought that it was an American spy plane, or that they thought that the South Korean 747 civilian passenger plane was being used for reconnaissance plane. They shot it down to cover up the fact that:
a) 10 days before KAL 007s flight, a North Pacific/Arctic storm had destroyed all of the far range air defense radars on the Kamchatka Peninsula, where KAL first overflew unmolested.
b) The Soviet general in the Soviet Far East told Moscow that all the damage had been made good within 48 hours.
c) He lied. All the spare parts for the radars had long ago been sold on the black market. (4)
d) KAL 007 made it all the way across the Sea of Okhotsk without being molested.
e) She was shot down only seconds from international airspace.
4) All to cover up the fact of Soviet black marketing and its effects on Soviet war making. Which is why, in the early 1980s at least, short of Strategic Surprise, I have a hard time with the concept of the Ten Foot Tall Ivan Ivanovich.
The more the Soviets try to mobilize, the more these shortcomings will be exposed. The question is, will anyone tell the Kremlin the truth? With KAL 007, Defense Minister Dmitry Ustinov told the Spy Plane Story to a (mostly) incredulous press. Did Ustinov lie himself, or had he bought the story told by the Soviet Far East Air Defense commander hook-line-and-sinker? I suspect that he didn't care anymore than the Soviet ADF general did.