Boeing Co (BA.N) is exploring a potential market of over 1,000 aircraft in a niche between its single-aisle 737 and wide-body 787, but has not decided whether to invest in a new jetliner, its sales chief said on Sunday. Speaking in an interview ahead of the Paris Airshow, John Wojick, senior vice president for global sales and marketing at Boeing Commercial Airplanes, said airlines were looking for an jetliner able to seat about 240 people with greater comfort, but just as efficiently as the smaller 737 workhorse.