volplane

noun

1. A steep, controlled dive, especially by an aircraft with the engine off.

verb

1. To perform a volplane.

   “1916, Wilfred Percy ("Billie") Nevill, letter, in 1991, Ruth Elwin Harris (editor), Billie: The Nevill Letters, 1914-1916, Julia Macrae, page 143, […] when well over the bosche lines & he volplaned home, just skimmed over our & the Bosche trenches, they all fired at him like sin, of course, and landed about 1000 yards back on a hill.”

   “Curtains of vapor drift back to reveal the Americans, volplaning along well inside ten meters and only a little faster than the balloon.”

2. To glide.