Archytas, a Greek philosopher who lived between 428 BC and 347 BC, is believed to be one of the first people to investigate the idea of flight. He created a steam-powered flying pigeon sometime during his lifetime; however, the exact timing of this invention is unknown. The naming of this device came from the fact that it resembled the shape of a pigeon: wings on either side and a pointed front like a beak. The pigeon contained an opening at its rear which was connected to a heated boiler. The steam produced by the heated water caused an increase in pressure that produced the force required to eject the pigeon, which was reported to fly for several hundred meters.

Source (text and image):

Reese, M. R. (2014). The steam-powered pigeon of Archytas—the flying machine of antiquity. Ancient Origins. Retreived from https://www.ancient-origins.net/ancient-technology/steam-powered-pigeon-archytas-flying-machine-antiquity-002179.