Well here it is:
Turn one, buy 2 fighters and 1 infantry.
I know this sounds really weird, but I think it opens up a key strategic opportunity that may at least be interesting, if not entirely effective - usually an aggressive German player will take Anglo-Egypt the first turn with his bship/trans sitting in seazone 15. Have your 2 initial fighters land in Caucasus the first turn, and mobilize your 2 newly built ones in Caucasus as well. On turn 2, your 4 fighters can assault the battleship/trans in sea zone 15 and usually destroy them! This is a harsh blow to Germany who is relying on that transport to get units into Africa, and the loss of the battleship is equally devastating because it removes both protection of his future transports there and the ability to bombard.
Germany will have to build a transport and some sort of good naval defense in Mediterranean if he ever wants to go into Africa again after that.
Of course, this lessens Russia’s ability to defend because you could have build a total of 8 infantry instead of 2 fighters and 1 infantry, and you’re losing maybe 2 fighters on average, so I would suggest only doing this either for fun or in combination with a true Kill Germany First strategy where the Western Allies can pressure Germany enough so he’s unable to take advantage of the lessened defense for Russia. Russia has done a good service in helping the UK keep Africa as well as allowing the US an easier time to sail through the Mediterranean.
I think the gains for this is at least worth the try once - it may not be as tried and true as the mass infantry defense, but it does have some alternative viability in it and provides for variety you don’t see with the 8 infantry build that is done nearly every game.