Will be interesting to see if the 737-10 gets certified before the end of the year regulation change deadline, which unless extended (which congress has to do) will then require an extensive rework to meet the new regulations and I would imagine significant delays. That might be why AS is keeping the A321neos around for a while, or would AS simply take more -9s? I also wonder if the -10 can fly westbound transcons in a strong winter jet stream without a fuel stop.