Boeing 'to unveil mega United Airlines order'

US planemaker Boeing was set to unveil on Thursday a firm order from United Airlines for 100 single-aisle 737 planes, including many future MAX jets, sources and reports said. "Boeing should announce a big order of 737s by (US airline) United," a source close to the deal told AFP. Boeing said it and United Airlines were to make a "major announcement" at the Farnborough airshow near London at 1400 GMT. The Seattle Times reported that the deal was for "a firm order for 100 of Boeing's single-aisle 737s, most of them the forthcoming model with new fuel-efficient engines, the 737 MAX." It added that the value of the deal could be up to $10 billion (8.2 billion euros) at list prices. It would also carry an option for the carrier to purchase 100 more planes, the paper added. Boeing's 737 MAX is an upgraded and more fuel-efficient version of the 737, the world's best-selling commercial airplane. The first 737 MAX is scheduled to be delivered in 2017 and is a response to the Airbus A320neo. Airbus says the A320neo, due to enter service in late 2015, will use 15 percent less fuel than its current best performing A320 model. Boeing's deal with United Airlines will help the US manufacturer to close the gap with European rival Airbus in the battle for orders of new short-haul plane models. Airbus has enjoyed great success in the upgraded single-aisle sector with more than 1,400 firm orders for its A320neo. Boeing's had 549 firm orders for the MAX prior to the United announcement due later on Thursday.