Originally Military and Nautical. Of a fort, ship, etc.: not provided with a person or a company of people as a crew, defensive force, etc…

Not equipped with or using a motor or engine.

That flaps. Applied spec. to the upward and downward movement of the wings of birds and, formerly, of flying machines. So flapping flight, etc.

Applied to flying across the country. Also absol., a cross-country flight.

Of or designating a fly-through.