The wing is swept back at 30 degrees, allowing a maximum operating Mach number of 0.86. To reach a long span and high aspect ratio without a large weight penalty, the wing has relatively high Thickness-to-chord ratio of 11.8% or 12.8%. Jet airliners have Thickness-to-chord ratios ranging from 9.4% (MD-11 or Boeing 747) to 13% (Avro RJ or 737 Classic). Each wing also has a tall winglet instead of the wingtip fences found on earlier Airbus aircraft. The failure of the ultra-high-bypass IAE SuperFan, promising around 15% better fuel burn, led to wing upgrades to compensate. Originally designed with a span, the wing was later extended to and finally to . This wingspan is similar to that of the larger Boeing 747-200, but with 35% less wing area.