Interest among European airlines in acquiring Mitsubishi Aircraft regional jets is focused primarily on a 100-seat version that the Japanese manufacturer has not officially launched, a senior executive with the Japanese manufacturer says.

“The demand over there will be for the larger aircraft,” Howard Thrall, senior vice president of Mitsubishi Aircraft Corp. America, said this week in Washington, where he was the featured speaker at a Japan International Transport Institute-hosted briefing on the future of regional jets. The aircraft Mitsubishi currently is marketing—the MRJ90 and MRJ70—can accommodate up to 92 and 78 seats, respectively.

Thrall did not flinch when someone suggested EasyJet as a potential customer in Europe, but also noted the Air France-KLM was an “active participant” in the MRJ working groups.

Thrall, however, tells Aviation Week that does not expect Mitsubishi Aircraft to make a decision on whether to launch an MRJ100X until the MRJ90 is certified and in service. The first MRJ90 jets are scheduled to be delivered to All Nippon Airways (ANA) in late 2015 or early 2016.

After ANA, the next customers in line for the jet are two U.S. regional airlines: Trans States Holdings in 2016 and SkyWest Inc. in 2017. Both have ordered the MRJ90: 50 firm and 50 on option at Trans States, and 100 firm and 100 on option at SkyWest.

All of the MRJ90 versions are listed with a maximum takeoff weight (MTOW) in excess of 86,000 lb. Most pilots union contracts with major U.S. carriers include scope clauses that forbid the airlines from outsourcing flying on aircraft above that MTOW, which eliminates the main source of business for regional airlines that acquire the jet.

Thrall, who is responsible for sales and marketing of the jet in the Americas, acknowledges that issue is a “conversation point” in discussions with customers and potential customers in the U.S. But he notes that the aircraft is being designed for the global marketplace, where such restrictions do not apply, and says he does not foresee a problem getting the aircraft certified at a lower MTOW in the U.S.—if that proves necessary.

“The other thing to keep in mind is that these scope limitations change over time,” he says, holding out the prospect that pilots unions will agree to relax the MTOW restrictions.

Thrall also adds that the contracts with SkyWest and Trans States provide “maximum flexibility” to those carriers. Although he did not fully describe what that means, SkyWest has said it has the option to change its order from the MRJ90 to the smaller MRJ70.