radeng, does that mean there's nuts loose on AA flights?
bardos, if you can't get a doctor to prescribe insulin for you (which I think should be the best treatment in most cases), dried meat (such as air-dried ham) will probably be more acceptable for your fellow passengers than sardines of all things. Also raw cucumbers and most types of green lettuce can be considered to contain no useful carbs, and make a refreshing change.
Any raw food you bring should be eaten up before landing though, if it's an international flight, or you may have to give it up at customs. Or just phone the airline and explain exactly which foods you can and can't eat. Some at least will be able to adapt.
That said, I'm a type I diabetic and your situation re treatment may be entirely different. But no subject drift intended...