UA has eliminated most of the Hawaii service, routing some tickets onto HA flights. With very strict rules out about interisland travel effective today, HA eliminated a large part of their interisland flight la too. I noticed UA is still selling tickets onto HA codeshares that no longer exist.
You shouldn't travel to/from Hawaii, its islands, and/or the mainland except for an urgent medical issue, but be aware what UA allows you to book and what was once in the schedule is very different from what's really flying in April.