PARIS (Reuters) – Airbus has begun lining up tentative orders for a longer-range version of its A321 jetliner, seeking to exploit signs of hesitation at arch-rival Boeing over whether to develop a new model in a hotly contested niche of the airplane market.

The European firm is in detailed talks with airlines over the price and timing of the longer-range design – known as A321XLR – and has penciled in some orders subject to a formal launch, expected this year, industry sources said.

Airbus is looking for 200-300 draft orders before committing to build the A321XLR, in a move that would limit the space available for a mid-market alternative that Boeing hopes to launch in a gap between medium-haul and long-haul jets.

“Every A321XLR that Airbus sells, means one less potential sale for the NMA (Boeing’s proposed New Mid-sized Airplane),” an industry source said.

An Airbus spokesman said the planemaker is “always talking to customers” and declined further comment.

The middle of the jet market is at the center of one of the most widely watched airplane design battles for years.

Boeing is aiming its potential new 220 to 260-seat NMA at a niche previously served by two models: its own 757, a long-range single-aisle jet, and its 767, a larger twin-aisle model.

Boeing dominates the upper end of that spectrum but has come under pressure from Airbus at the lower end.