With so many labour contracts in play, one of the main objectives for US mainline carriers will be further scope clause relief, as suggested by Continental, which is at such a competitive disadvantage in being unable to operate any regional jet larger than 50 seats. Should past contract agreements be prologue, then it is highly likely that pilots will trade scope relief for gaining their top objectives ultimately by ceding mainline narrowbody flying in the US domestic market, according to MIT International Center for Air Transportation Research Engineer, Bill Swelbar. The impact could have a profound impact not only regionals, but on the aircraft now in development and coming to delivery in the next few years.