Traveling by air from Miami to Seattle

[Lola RB]

Hi everybody!
I'm planning a trip from Miami to seattle on the first week of November.
I'm planning to take Lola (She will be 7 - 8 months by then).
Has anybody have any experience flying with your boxer on Alaska Airlines?
Should I get a sweater for her. I don't want her to get too cold o her way and when arriving in Seattle.
I will be taking a non-stop flight.
Please help me out. Any suggestions are truely appreciated.

Thanks you