Yarggh! Hubby and I are flying from San Francisco to Okinawa at Christmas on United. The first leg is ~13 hours, then a four-hour layover in Osaka, then two more hours to Naha. (We're buying flight insurance for the first time just in case.)
Have you priced JAL instead? It might be well worth your time to check out their price. I would fly JAL to Japan before any domestic carrier.