Okay so I went with airport to airport cargo. 7-8 hours in bag and they were fine, shipping was a success. Thanks for all those who helped with this, much appreciated. I only had a couple minor issues: tying off the bag once full of oxygen was a massive PITA, twisting the top, folding, and putting tons of elastics. Bags seemed to deflate a tiny bit after the 2 hour drive to airport, but obviously they held up fine. The bigger issue was that the heat pack was pretty hot, and it was actually 8 degrees when they left here and 2 degrees on arrival. I didn't exactly know the temperature these guys would be subjected to so I left the heat pack in, but I know it got pretty hot in the box. At what temperature do you guys not use heat packs? Do you still throw one in the spring, and none in the summer? Or after it hits 10 degrees plus don't bother? I only used one this time around which was the best call I made, if temperatures were below freezing I would have used 2, just not positive when to let em go without one. After that basically I know what I need to about shipping, which really helps.