I personally would not do it. I was recently on a flight that was supposed to be 4 hours total. It ended up being 12 hours as we were delayed then rerouted then an emergency landing to refuel
Sugar Baby was in the cabin with me. I was able to get her out of her carrier and also let her walk around and potty, hand feed her water through a syringe and feed her the homecooked meal I had brought along.
What if she had been in the belly of the plane??
How much does your little guy weigh? Is he prone to bouts of hypoglycemia??