Contrails

There is much confusion and misinformation about a common phenomenon in the sky known as contrails (condensation trails). They have been common ever since aircraft were able to fly at high altitudes. Some conspiracy theorists are saying they are chemtrails; part of a government plot. This is not the case. at all

Contrails over Stormstown, PA on October 6, 2022, at 8 AM EDT (12z).

There are two byproducts that result from the burning of aviation fuel, a mixture of hydrocarbons: carbon dioxide and dihydrogen monoxide (water vapor). Water vapor is what comprises a contrail.

GFS Sounding for 8 AM EDT (12z) on October 6, 2022
The red line is the temperature and the green line is the dew point.

Stormstown is near a busy airway for east-west as well as north-south traffic. The aircraft that expelled the water vapor were at roughly 30000′ ASL or roughly at the 300 millibars (hPa) level. From the sounding (above) made at the same time as the photograph, the temperature at that height is less than -40 deg C or -40 deg F. Under those conditions, any moisture would condense as ice particles which form the contrails. The contrails persisted and became cirrostratus clouds due to the fact that the air temperature was close to the dew point, close to saturation, at that level.