United has been canceling some flights as well. When we booked SFO-BOS for a September cruise, there were 3 non-stop flights that worked...6am, 7am and 8:30am. We booked the 7am. A month later, they cut that to one flight...8:30, and merged everyone into that flight.
Some cancelation of flights can easily be caused by slow resumption of service to some places due to lack of demand post Covid. Like China, for example.