Best quick and clean way I know, is coming up very fast from behind, zooming up, hitting the gunned plane's wintip with all guns, continue zoom as he starts to tip over, begin timing.
Roll over so that you come down onto the next fresh bomber (if he auto-destructed the tip-less one) just as he's transfered to it, slash back down onto that one's wingtip, and most of the time, by this time you are safe enough to just walk over almost any way to the third one's wingtip.
If the guy does not bail for some reason, you have to follow the formation fast enough to catch at least one more plane's wingtip, before it does the see-saw warping.
If the guy is very fast to bail from the first tip-less plane and guns well, you are back to square one, and the safest way is to continue up and out of its 50cals' range, and repeat from the beginning.
Another sure way if you've practiced enough is to barrel around and around on the same heading as the formation, not exactly on a formation-centered axis (to fool his aim), and shoot at one wingtip at a time, each time you're coming down in your barrel.
