As the economic metric of the 50 now is undesirable so will the 70 seater as oil becomes expensive enough to point where it will make it so. If oil becomes high enough look out for the Q as a replacement for the shorter feed routes. Very economical aircraft, especially if the carrier opts for pax O2
to operate in the 30's flight levels. I see these and the 90-120 seater as the future. UAL/CAL ALPA, make sure you account for those Q's in your contract!