How do planes write in the sky?

Planes write in the sky using a technique called skywriting, where a pilot releases a special type of smoke, usually made from a mixture of oil and other chemicals, from the aircraft's exhaust. The smoke forms letters and shapes as the plane maneuvers through the air, creating visible trails. The pilot carefully controls altitude, speed, and turns to create the desired message. Conditions like wind and weather can affect the clarity and longevity of the writing.