I believe it was Molders, while flying with the Condor Legion in spain, who devised the so-called finger four fighter formation [two pairs of wingmen] still in use today.
It's hard to say really. Charles Chennault was experimenting with double-plane and triple-plane formations back in 1929. One configuration consisted of two sets of the double-plane formation which was identical to the fingers four. A formation that good is likely to be developed by many independent from each other.