The plane pulled the red line so slowly. What happened?

The weather is windy, the temperature is high and the air humidity is low. The red line is the flight trajectory of the aircraft engine, which is scattered or refracted by sunlight to form the red line. When the weather is windy, the temperature is high and the air humidity is low, the plane slowly pulls the red line. The scientific name of the plane's stay is the wake cloud. This kind of cloud will not exist for a long time and will usually disappear soon, but it can exist for more than 1 hour under favorable conditions and can expand into a relatively broad cloud layer.