I believe those winglets are third party, approved by Boeing, if not mistaken. All this fuel efficient moves, even the A320s have them.. (which is odd because I recall Aribus says that the A320s' wings cannot handle the extra weight for the winglets on the A320. Perhaps either they came up with a winglet that is lightweight, or they found it doesn't make much difference, or they just 'winged it'. Geddit? Wing?

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