Drawings of Contrails - White Lines Across the Sky
Contrails are vapor trails that form from the exhaust created by a plane's engines, and they can also form when the plane moves through a change in air pressure. Depending on the conditions, contrails can disappear in a few seconds or eventually become clouds.
These days, they're a less common sight due to the drop in air travel. But you'll always be able to see them on pixiv!
How do the skies look in your area?

蒼群
by 心象Sketcher

Skywatcher
by LB