What planes leave a white trail?

Jets leave white trails, or contrails, in their wakes for the same reason you can sometimes see your breath. The hot, humid exhaust from jet engines mixes with the atmosphere, which at high altitude is of much lower vapor pressure and temperature than the exhaust gas.



People Also Ask

Not all aircraft produce contrails – they are estimated to occur in about 18% of flights. The air needs to be cool enough for the water to freeze, which is why they usually only appear above certain altitudes – typically 20,000ft (6km) Even fewer flights produce the most persistent contrails.

MORE DETAILS

Thus, these contrails indicate regions where there is strong wake turbulence caused by the aircraft in front of you that made the clouds. Heavier, slower aircraft make more intense wake turbulence.

MORE DETAILS

While fuel dumps don't happen every day, they're also not uncommon. Nor do they usually represent a major emergency. In fact if an aircraft is taking the time to dump fuel before landing, that's likely an indication that the issue forcing the plane to land is serious but not critical.

MORE DETAILS

Contrails are human-induced clouds that only form at very high altitudes (usually above 8 km - about 26,000 ft) where the air is extremely cold (less than -40°C). Because of this contrails form not when an airplane is taking off or landing, but while it is at cruise altitude.

MORE DETAILS