Sure, helicopters are just preposterous... but where would the US Navy, Marines, and Coast Guard be without them? The NMNA has many superb egg-beaters on display; I'll let the experts identify them.
Nice. I swear we have another #3 shot in what was the bristol industrial museum.
When once you have tasted flight, you will forever walk the earth with your eyes turned skyward, for there you have been, and there you will always long to return – Leonardo da Vinci.