white streaks in the sky

Why often have white smoke streaks in the sky after the plane flies over?
the white stain is the exhaust of an airplane engine that is emitted in the sky and due to the difference in temperature and humidity in the air that causes the steam in the exhaust gas to condense in the atmosphere.
Aircraft and 11 unexpected secrets that not everyone knows
there are interesting secrets about airplanes that not everyone knows about: what happens if the airplane engine fails while flying or the aircraft is struck by lightning, the safest seat on the plane ...