Originally Posted by GUWonder
Some countries put some of their MREs in metal wrap of sorts that does set of the alarms and/or cannot be viewed by the x-ray when there are a bunch of them stacked together in a bag.
The military type MRE's do have some metal in them. The inner pouches have a very thin foil to protect the food.
The flexible aluminum retort pouches used in MRE pouched food products are composed of multiple laminations of aluminum foil and plastic film. Rugged durability, extended shelf life and ease of stowing have earned the MRE pouch a well-deserved nickname "the flexible can"
In addition, the military MRE's come with the so-called "flameless heater" which is a water activated reaction on 2 metals (Fe and Mg??) that produces heat and hydrogen gas. As a device that could produce a flammable gas, these will probably fall under the DOT ban. These military MRE's are not allowed to be shiped by civil air (UPS ground only)
If they are "civilian" MRE's (e.g. SPOACO) there is no heater and aside from the aluminum foil should be OK to fly