To keep the bacteria alive (which is what makes it cycled) it needs to be constantly moist, and because the bacteria are aerobic, they need oxygen, but since the air we breath is 21% oxygen, just putting a decent amount of air in the bag is sufficient. The bacteria also need moderate temperatures throughout shipping, but will withstand colder temps. than many fish. To keep the bacteria alive for a long period without fish or other (food) source one could use water that has a small amount of Amonium chloride added to it to provide a food source, but that should only be needed if the shipping is going to take longer than a couple days.