Always fly the day before UNLESS

You love stress and risk and
you let the cruise line do the air and guaranty that if you miss the ship, at their expense they will get you to the next port and allow you to board.

This guaranty is not always available. I usually use miles as it seems you are doing so this doesn't work anyway.

If overseas, we go two days early to have time to recover from the flight and see the port city.