Originally Posted by
WineCountryUA
As PDX-IAD is / has been an A320 route, the MAX impact is indirect and speculative at best
Yes, but I think it's generally true that UA might be trying to increase utilization out of its entire narrowbody fleet while the MAX is grounded. Taking a plane, an A320 in this case, and flying it through the night instead of parking it overnight, increases the utilization of that particular fleet. The cumulative effect of all fleets being better utilized helps offset the capacity loss from the MAX grounding.
But why, now, the schedule change? Because July is now six-weeks away, and that's when schedules often get the "final touch". It may be that the schedule prior to now was preliminary, and it might not have completely factored-in the impacts of the MAX grounding... until now.