The US Army did.
The first practical helicopter built was the Sikorsky VS300, as in pic.
Igor Sikorski was well on the way with inventing the first practical helicopter then
US Helicopter ended in 2009.
US Helicopter was created in 2004.
US Army helicopters landed in South Vietnam in 1956. They were used in the Korean War in 1950-53.
The first road accident in the US is not on record.
Second World War. Germany was the first to use them, as air ambulances. The US followed shortly after, using them as observation and reconnaissance platforms.
what city in the u.s became the first to install an electric traffic light
Dwight Eisenhower was the first to have a presidential heliocopter, starting in 1957.
Igor Sikorski was an aircraft designer in Russia. But he came to the US and began to build helicopters. Many of his helicopter designs were used in the military. In 1943, Larry Bell who owned Bell Aerospace was convinced of a helicopter design after seeing a remote controlled model built and flown by Arthur Young. Bell set-up a design shop in Garden Park, NY where the first Bell Helicopter was built. This prototype evolved to become the Bell Model 47---the first helicopter to receive FAA Certification.
The SUPER Cobra (two engines instead of one) is a "post" Vietnam helicopter used by the USMC because it was cheaper to buy than the newe APACHE attack helicopter.