Commercial Aviation commenced after World War I using mostly ex-military aircraft for the purpose of transporting people and goods for the purpose of making a profit. Its first profitable cargo was usually air mail, which was the means by which governments subsidized air travel. Within years, many lines criss-crossed Europe and North America.
It became vital after World War II due to the introduction of Jetliners that were able to transport masses of people economically within a small amount of time.
