I took a look at a few of UA Asian inbound flights, and see that many are in-flight/have arrived. E.g.: UA 876 (NRT-SEA in flight); UA806 and 896 arrived in SFO and ORD respectively. Note that the domestic continuations seem to be cancelled.

As of now, UA801 (JFK-HKG) is in-flight after a 98 minute delay, and UA895 ORD-HKG is still scheduled to leave within the hour.

I can only commend everyone at UA for doing such a wonderful job of moving forward in these extremely trying times.