Go buy some boxes of heavy duty freezer bags, A cheap throw away plastic storage bin or your ice chest, 10-15 lbs of coarse rock salt (Ice cream salt), Once your fish are fileted put what ever you want in each bag (double bag them) suck the air out by submersing your filets about an inch above the water and zip shut (go on you tube for examples) Then fill your bin with lots of ice, water then add dry ice (again go on you tube for ratios of water salt and ice) stir around for 5 minutes, drop bags in slush and in 15 minutes and they will be frozen solid. Pack the bags of frozen fish in soft cooler and off to the airport. It may take 1-3 hrs depending on how many bags you have. Try at home with smaller amounts and see how quick things can freeze. That's an option if you can't get them packed and frozen. Good Luck