Hey Black, how goes your flying?
Regarding your specific question, I don't know at what point WWII tactical doctrine allowed the wingman the freedom to maneuver on his own but just the CYA dictum would eventually force them out of their welded wing formation. The question would be "what then"?
Now days a true 2v2 (or 2v3, 2v4) would evolve quite a bit differently as it's based on entering a fight in a very aggressive manner from a wide combat spread formation, many times with a significant altitude split. With modern fighters the spead formation can be up a mile to mile and a half apart. This reflects relative turn radius, the high speeds and the SA provided by modern radar and of course, missiles. A jet can be a mile away and still be able to shoot a bandit off your six in a few seconds. In AH, I'd say a good spread formation would probably be much closer to 1k or less.
Until the merge, and all things being equal, the flight lead's going to maneuver the section into the fight unless his wingman has better Situational Awareness, then the wing would become the tactical lead. An example would be the wingman picks up the bandits at close range at his 9 o'clock and the lead doesn't see them.
In the engagement the mindset is one of mutual support between two equals vice what sounds to me more like shooter/lookout or maybe more accurately shooter/bullet sponge relationship. Of course we don't have guys flying wing nowdays with only 20 hours of flight time either.
Once engaged the concept of Lead and Wing don't mean much at all, it's a cooperative effort with a goal of 1) keeping sight of each other (and clearing your buddie's six), 2) keeping sight of both nme 3) remaining close enough to provide mutual support and 4) communicating and cooperating.
Now to answer your specific question. How and who you engage depends on the tactical situation. Two aircraft flying welded wing a'la WWII tactics can be treated as one as long as they stay together. In modern lingo by staying together they are said to be flying "in phase" and any maneuver(i.e., immelman, flat turn, reversal, etc.) you do against one works against both of them, essentially the fight is a 2v1. For them they have a big problem because a defensive move on their part ONLY works against one of the fighters while usually giving an advantage to the other. In this scenario what would happen is both fighters will maneuver out of phase with each other and use a concept of free fighter and engaged fighter. The engaged fighter is pushing the bandits hard looking for a kill shot, the free fighter usually positions high or extends a bit to time his attack based on where the engaged fighter is pushing the bandits. He then comes nose on-from a position of advantage and becomes the engaged fighter and both fighters exchange rolls.
Now lets say the bandits are operating using the same tactics as you are and arrive at the fight in a good offensive combat spread. This starts out similar to two interlacing 1v1s but the difference here now becomes shots of opportunity on the other fighters bandit and the concept of switching. Lets say you come out of your first turn neutral with your bandit but a very good position on the second, you'd call a switch and take the second and your wingman takes yours. In an extended engagement these switches would occur frequently in a well coordinated fight.
Last case, assume the bandits are operating with very wide separation, maybe something like a long lead/trail formation where the wingman cannot engage immediately. The fighters need to decide who is the high threat bandit and engage him first. For instance, say the lead bandit is below you but the trail has several thousand feet of altitude advantage. This would actually make the far bandit a greater threat so the fighters might blow past the first bandit and engage the second. Again the fighters will use free and engaged concepts but in this case the free fighter's primary responsibility is being ready to engage the low threat bandit when he approaches. As you say, the goal would be to reduce a 2v2 to a 2v1 quickly.
In any of these cases if your bandit starts to bugout while your wingman is heavily engaged with the other then a decision needs to be made regarding following your bandit. He could have had enough and is going home, he could be simply trying to break down the fight into two separate 1v1s or he could just be extending so he can re-enter the fight with a better tactical position, (this is called "redefining" a fight). If you're only a few seconds from killing him and your wingman is offensive with his bandit then do it. If not you need to stay with your wingman while keeping sight of the departing bandit and watching for him, or another to enter the fight. This is where I see mutual support breaking down most often in AH. A running bandit almost always gathers a crowd of fighters which then will often leave some poor guy to get his butt shot off.
Mace
