There have been too many UFO sightings from ancient times to the present, so much so that even Su Shi, a great poet of the Song dynasty, had an experience of witnessing UFOs. He even wrote a poem about it.
"At that moment, the newfound moon's glow faintly lit up the sky,
In the second watch, the moon set and the sky turned pitch black.
It seemed as if torches glowed bright on the river,
Flying flames startled perched birds by the mountains, casting their light.
With a heavy heart, I returned to my bed, my mind unable to discern,
Neither ghost nor human, what on earth could it be?
If the landscape isn't inviting, don't return to the mountains,
The river god shows me wonders, warning against my obstinance."
Of course, Yang Yi could recite this poem about You Jinshan Temple, but he wasn't interested in aliens and unidentified flying objects.