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DUBAI, Nov 16 (Reuters) - Boeing denied it was pushing to accelerate development of its newest jet to get an edge on its European rival, saying on Saturday it was sticking to plans to deliver it in mid-2020.

A union leader said on Friday that labour contract talks linked to production of the 777X aircraft were driven by Boeing's desire to "expedite development" after recent wins by Airbus.

"There is no change of schedule," Marty Bentrott, senior vice president for international sales, told a news conference ahead of the Dubai Airshow.

Boeing officials declined to discuss orders lined up for the Nov. 17-21 air show, but Bentrott said the 777X had been received "very positively" by all three major Gulf carriers, referring to Emirates, Etihad Airways and Qatar Airways.

Boeing expects to resolve reliability problems with its high-tech 787 Dreamliner within six months by rolling out changes to the aircraft's software, he added.

Customers including Qatar Airways and Norwegian Air have complained about the plane's reliability.

Bentrott predicted the Dreamliner's latest version, the 787-10, would be part of the Middle East's fast-growing fleet and said he was confident about prospects for the 737 MAX.

Industry sources have said the 777X will be formally launched at Sunday's opening of the Dubai Airshow with as many as 250 orders for the twin-engined aircraft, which will include the world's longest-range jetliner among its two variants.

Industry sources also expect heavy orders at the Middle East's largest aviation gathering to include 30 Dreamliners and a 75-plane order for the Boeing 737 MAX, as well orders for all sizes of Airbus jets.

(Reporting by Tim Hepher; Editing by Michael Perry)