I agree. I developed a severe allergy to iodine after using it to disinfect water for just 4 weekends. It caused a deep-seated rash (lichen planus) that left permanent scars. I still cannot eat anything made with iodized salt or any seafood. For emergency water disinfection, I strongly recommend some form of chlorine dioxide (such as Katadyn or Aqua Mira tablets) instead. Believe me, you don't want to risk what I went through!

The flint and char cloth are totally unnecessary. Besides, in a true emergency--most likely a situation where hypothermia is imminent--you'll have a really hard time using them when you're shivering, your hands are numb and all the wood is sopping wet. I take a mini-Bic lighter, a paper match book, and, as a third backup, about a dozen of the REI emergency matches (they stay lit for a long time and, IMHO, are the best thing REI has ever come up with), and half an Esbit tablet. There's an excellent reason that our ancestors with their wood or coal fireplaces and stoves abandoned flint and steel as soon as matches became available!

What you can't carry on the plane, even in checked luggage, is fuel. Sharp points (knives, trekking poles) and liquids also need to go in checked luggage.