Well, I was thinking purely about propelling an object that is heavier than air versus lighter than air. An airplane only stays aloft as long as it is being pr

Well, I was thinking purely about propelling an object that is heavier than air versus lighter than air. An airplane only stays aloft as long as it is being propelled, after that, it's basically falling with style. Likewise, a lighter than air craft is just floating in the wind without being propelled, so the key is which is easier to propel, thus, it compares well to just throwing an object.