Thanks everyone for your suggestions.

No, it's not a charter, it's Alaska. Unfortunately there are no longer any other flights to choose from. With a little digging I found that the flights jump to this new schedule just 2 weeks before our departure. And I still haven't received any official correspondence from the airline regarding this dramatic change in schedule. (I found out by accident when I tried to check seat assignments on-line and was told to call the airline.)

Canceling the trip would mean other financial penalties. Most of our hotels in Mexico required full payment when we made the reservations... even those booked thru this airline's Vacation department.

I feel like we're stuck between a rock and a hard place.