This seems to pop up more and more often. I've had cancellations on transcon JFK-LAX, all flights after 15.00 om July 3, in fact when realizing I couldn't get to LAX that night, I rebooked to 10.00 next day, Looking for some little MR/TPR on the afternoon and eve of July 3, returning early morning next day to JFK was in vain, as all but 2 or 3 flights (with interest from this aspect) out of JFK after 15.00 also were cancelled. Those that weren't had the morning return cancelled instead.