Skywriting works using a special type of oil that's injected into the airplane's exhaust manifold. ... As the airplane burns fuel, it will create hot temperatures in and around the exhaust manifold. With its hot temperatures, the exhaust manifold will then vaporize the special oil.

What is the purpose of sky writing?

Forming words with Skywriting can help one's mind to memorize how letters fit together for correct spelling. It helps students to gain confidence with their spelling as they piece together, letter by letter, the words they are attempting to spell.

Is sky writing illegal?

Skywriting and skytyping were banned by the government in 1960 because of concerns over safety and the potential spread of political propaganda. However officials are now planning to change the law to allow the creation of mid-air advertising slogans, birthday greetings and marriage proposals.