Looking at the Airbus A320 family, one can observe variations in winglets. Older models might have no winglets, resembling designs from the 1980s. Some feature a triangular wingtip fence extending above and below the wing, while newer models boast 'Sharklets', which are blended winglets with a curve similar to a shark's fin.
The A320 played a significant role in airplane wing design evolution. Blended winglets, seen on many modern aircraft, offer benefits like reduced drag and improved fuel efficiency. An Airbus retrofit package allows older A320s to be fitted with Sharklets for enhanced performance.
Wingtip fences were first introduced on an airliner with the Airbus A310-300 in 1985. They reduce drag by directing airflow smoothly off the wingtips, decreasing wake vortices. Benefits include reduced take-off distance, higher cruise altitudes, increased fuel economy, and decreased turbulence intensity.