Airbus introduced larger winglets for the A350-900 and -1000 jets as part of several aerodynamic improvements.
The new A350-900 to Iberia airlines is the very first aircraft delivered with the latest performance improvement package, including new winglets.
The new winglets increases the aircraft’s ‘effective wingspan’ by 212 feet, without increasing its geometric wingspan.
Airbus pioneered the use of wingtip devices in commercial air transportation, beginning with the A300 and A310.
The winglets change the spanwise pressure distribution of the wing, but does not change the way the wingtip vortices are flowing.
The winglet and the slight spanwise wing twist changes the airflow around and behind the wing. This change of the flow pattern is what reduces the drag, not the vortices around the wingtips.
The purpose of winglets is to slow down the circular motion of the air around the wing, so to get an even wider and more optimal spanload distribution. The optimal spanload distribution significantly reduces induced drag… thus reduces fuel consumption.