Before leaving for Iceland, I was a bit worried about flying the military-issue Meals, Ready to Eat packs.
The answers I got from the Delta Airlines and the TSA were less than definitive – Icelandair was crystal-clear: They’re okay in checked luggage.
The good news is that I had no problems flying with my MRE packs. I went through security screening at three different airports (Phoenix Sky Harbor, JFK/New York and Keflavik International) and customs at two of them, and had nary an MRE-related problem (the monosyllabic and surly “instructions” of the wonderful Customs staff at JFK, however, was another story. Only one of that lot was even remotely pleasant.).
Based on my experience, you should have no problems if you put your MREs in your checked luggage and keep the packages sealed. Still, always check with your airline. Policies and regulations are always a moving target, and a terrorism-related panic du jour always seems to be around the corner waiting to monkeywrench travelers’ plans.