Essence

Essence is a funny word. It is existence itself - esse means "to be" in Latin - and
touches the core of its object. Over time we have refined its usage, adding perfumes and foods - the essential oils. France goes further; there, airplanes (and cars, and trucks) are powered by essence.

Thus fuel becomes the essence of flying. Sailplane pilots roar in protest, but theirs is a narrow view. Fuel stores energy, but only of a particular kind, and when lacking we find a different source.

Energy - whether from fuel or the brain - keeps us aloft, moving forward, but not yet feeling good. The finishing touch - the finesse - completes the cycle.

Finesse is the end of flying, not the perfect landing but the very purpose. Finesse describes the wing, in a particular way. The usage has not taken off in English, but in French it describes the performance of the wing.

Energy and the wing: that's flying.