In about 1420, da Fontana wrote: “I, indeed, have no doubt that it is possible to attach to a man wings which may be artificially moved, by means of which he will be able to raise himself into the air and move from place to place and climb towers and cross water. ”
Ap 1420. gadu da Fontāna rakstīja: ” Man nav nekādu šaubu, ka ir iespējams piestiprināt cilvēkam mākslīgi kustināmus spārnus, ar kuru palīdzību viņš varēs pacelties gaisā un pārvietoties no vienas vietas uz otru, rāpties torņos un šķērsot ūdeņus. ”