Before revision: Helicopters and Air Taxi Services Beginning in the early 1950s, air operators offered UAM air taxis services via helicopters in a handful of U.S. cities, including New York, Los Angeles, and San Francisco.
After revision: Helicopters and air taxi services Beginning in the early 1950s, air operators offered UAM air taxis services via helicopters in a handful of U.S. cities, including New York, Los Angeles, and San Francisco.