SkyWest’s 100-aircraft tentative order for the Mitsubishi Regional Jet is for the MRJ90, the larger of the two versions, but the deal also gives the U.S. regional carrier the flexibility to convert all or part of the order to the smaller MRJ70, CFO Michael Kraupp tells Aviation Week.

The eventual type or mix of types will depend on what happens with scope clauses at the major U.S. carriers that contract SkyWest to feed their networks. Kraupp says he believes SkyWest, the parent company of SkyWest Airlines and ExpressJet Airlines, can make that decision as late as one year before the first MRJ is delivered.

Currently, the airlines for which SkyWest operates most of its aircraft—Delta Air Lines and United Airlines—have scope clause limits that restrict regional feed to 76- and 70-seat aircraft, respectively.

Delta recently reached a new agreement with its pilots union that sustains its cap, but United is pushing for a higher limit in negotiations on a joint contract with its pilots and those of the former Continental Airlines.

American Airlines, a potential future SkyWest customer, also is pushing for a higher cap, using the leverage created by its Chapter 11 bankruptcy proceedings, and US Airways already is able to outsource some flying to aircraft with as many as 86 seats.

The MRJ90 and MRJ70 are designed to seat up to 92 and 78 passengers, respectively, in a single class with 29-in. seat pitch, but can provide fewer seats with larger pitch or in a two-class configuration.

“We’ll see where scope clause shakes out,” Kraupp says