Transporting milk home on flight?

Hello, ladies. In a week I'm heading out of town for a Bachelorette Party for a long weekend (Thursday night thru Sunday morning). I'm currently nursing my 4 month old so I will be pumping while away. What is the best way to transport my milk home on the plane? It's a short flight (1.5 hours) and door-to-door timeframe will be about 5 hours. I plan to check my bag and put a small hard-sided cooler with ice packs inside. I'll have access to a fridge and freezer while away. Should I freeze the milk beforehand, or keep it liquid? Package in bottles or bags? Any tips or advice is greatly appreciated!