AERO-ALPHABET - Op

Opel (Fritz von Opel) {ErZ}
Opel RAK.1 (Opel-Hatry RAK.1 . Opel-Sander RAK.1)

Opener (Opener Inc. - Palo Alto, California, United States) {ErZ}
Opener BlackFly

Öppulennuk
Öppulennuk PTO-4

Optery X (Optery X Engineering Ltd.)
Optery X MXIII

Option Air (Option Air Reno (Carl O. Barlow) - Reno . NV . USA)
Option Air Acapella 100-L
Option Air Acapella 200-L
Option Air Acapella 200-S