February 18, 1921. Œhmichen helicopter no 1, ships, Egyptian self rule, and Argentine arms.

The early history of the helicopter is complicated, and therefore capable of dispute.  Most early flights weren't that, but hops.  

This is the first "lift" of an Œhmichen helicopter. The gas bags were for stabilization.  Obviously, this would have been a completely useless design but it was pioneering, and the inventor went on to some significant developments in helicopter features.  Etienne Œhmichen was a biologist by training and employment.

The USS Hull, a Clemson Class destroyer was launched.

It was another short-lived post World War One U.S. Navy destroyer, and was scrapped in 1931.

On the same day, the USS North Carolina, a Tennessee Class armored cruiser of long service, was decommissioned.

The Armenian government fled the country's capital in the face of the Soviet invasion.  The U.S., which had declined to ratify the Versailles Treaty, left the Allied Reparations Commission.  Lord Milner, a now retired Secretary of State for the Colonies, presented his commissioned report to the House of Commons which argued for the immediate granting of self governance to Egypt.  Argentina, a German customer for arms, refused to stop purchasing the same from the same.