contrail

They reminisced about quiet city centres and skies clear of contrails.

When a plane passes through cold humid air, the contrails form as the vapour from the engines condenses on unburned fuel fragments in the exhaust stream.

These are actually condensed water vapour trails - known as contrails - that come from the jet engines of planes.

“Those contrails of the big jets overwhelmed me. It was my destiny to fly.”

The plane passing over Montreal during the partial phase of the eclipse left a typical contrail in its wake.