The innovative WheelTug electric drive system uses high-performance electric motors, installed in the nose gear wheels of an aircraft, to provide full mobility on the ground without the use of the aircraft's jet engines or tugs for pushback and taxi operations. The electric WheelTug unit needs only four pounds of fuel per minute by using the aircraft's auxiliary power unit (APU), representing an 80% reduction in ground operation fuel consumption. In addition to lower ground operation fuel consumption, other benefits of the WheelTug aircraft drive systems include substantially reduced carbon dioxide and other greenhouse gas emissions. Editors noted that WheelTug has placed something on the market that is ahead of the competition and uses a business model that makes benefits of the system measurable. The proof is in the customer list, with 573 delivery slots reserved by 11 airlines from Europe, America, the Middle East and the Far East by June 2013.