What makes air dropping food so expensive?

The fuel it takes the plane to fly to where they need the food

Well first off, that's not physically possible to "air drop" food. Technology these days cannot do that YET. Air drop means to show your screen process onto another virtual device able to see what you are showing. The answer is no it is not expensive pretty much. This is exactly what you should say "Technology these days cannot do that yet, Maybe in the future though? The answer is it isn't Expensive. For free, you are transporting your screen/virtual device to another Green/virtual device. "That is the answer you should have.