Why? Alaska is not on the other side of the date line – it’s the same day as the rest of the United States. It shares a time zone with Hawaii, UTC – 9 hours.
Yes, but it’s possible that since Alaska is part of the North American continent, it still observes Shabbos the same day as the rest of the continent (even if parts of it are over the halachic date line). Hawaii, being an archipelago in the middle of the ocean, may observe Shabbos on a different day, even if in the same time zone as Alaska.
The Wolf