We were booked on United nonstop AUA-IAD (Washington Dulles) on a Sunday in early December. I booked the flight back in March and didn't give it any thought until I got an email today stating a change to our flight. They changed us to the Saturday flight. I called, turns out they have cancelled some of their Sunday non-stops to and from Dulles, except during peak travel times. If you are booked on a Sunday flight on United to or from Dulles, check your itinerary.
It seemed kind of odd to me that they just put us on a flight a day earlier, but that's the industry I guess. Our only options were either 2 stops, a 9 hour layover, or landing at a different airport. Since we usually park at the airport, that would have been a huge inconvenience. We ended up cancelling the flight all together and luckily we were able to rebook on another airline with one stop for about the same price.-