May 1918

Thursday 02:

General Motors acquires the Chevrolet Motor Company of Delaware.

Wednesday 15:

The US Post Office Department (later renamed the USPS) begins the first regular airmail service in the world (between New York City, Philadelphia and Washington, DC).

Thursday 16:

The Sedition Act is passed by the U.S. Congress, making criticism of the government a jailable offense.

Monday 20:

For the third consecutive year on this date, the U.S. town of Codell, Kansas, is struck by a tornado.

Sunday 26:

The Democratic Republic of Georgia is established.

Tuesday 28:

Independence day in the Azerbaijan Republic.