I tried to book Christmas air tickets to Hawaii by Alaska Airline.

I checked Alaska Airline web site and there are only refundable tickets available and it costs $1500 round trip.

However, when I search for the same itinerary on American Airline website, the same flight (with AA code share) only costs $920.

It's kind of strange. Why the same Alaska Airline tickets is sold at much cheaper price by a partner? Is this normal for Alaska Airline tickets?

Thanks.