Answer:
The edge of earth and bread.
Four kings of whom I am one lord. Often on deck but never on board. Though I have a large heart, I am always seen at war. During which I always wear a suit, but never a suit of armor. Who or what am I?
If you are unsure how to use one then just ask a flight attendant.
I'm a starchy plant tuber that is one of the most important food crops, cooked and eaten fried, such as french fries.
You can do this with your friends. You can do this with your nose. But don't do it with your friend's nose!
What is lighter than what it is made of?