While winglets have been available as an upgrade for airliners for decades, the sudden rise in the cost of fuel has seen demand surge as operators aim to eke out every last bit of efficiency from their aircraft.
The Boeing 737 is the only mainline airliner in production to be offered with winglets as an option. The airframer says the upgrade can reduce fuel consumption (or boost range) by up to 4%. Airbus has been evaluating winglet designs for its A320 family and is about to launch a third round of test flights using a design developed by Aviation Partners. If successful, a decision to offer the upgrade could be made before year-end.
Aviation Partners Boeing winglets became available as an option on new-build 737s (and for retrofit) in 2001 and have been delivered on the -700/800 as well as being standard on the -900ER. Boeing reports that around 90% of 737s leaving the factory are winglet-equipped. Flight's ACAS database shows that the ratio has risen further in 2008, with 94% of the 103 737-700/800s delivered during the first four months of the year winglet-equipped.
APB expanded its 737 winglet offering to include the 737-300/500 and 757-200 in 2003/2007 and 2005, respectively. The largest operator of winglet-equipped Boeings (where winglets are not standard fit) is Southwest Airlines with 348 aircraft in service. As the table (above) illustrates, the majority of operators in the top 10 are North American based. Ryanair is the biggest European operator, with 165 winglet-equipped 737-800s.