Helicopters can fly directly up or down.
Because the air gets too thin.
Because rotors are noisy and helicopters isually fly close to ground
They fly helicopters.
Most helicopters fly with only one rotor. If you mean one blade, that is because it would be unbalanced.
Less than an hour. Now some can fly over 6 hours
No, Helicopters cannot fly in Stratosphere. It is too high for them. They do not produce that much lift. But they can fly in the Troposphere.
hah lol that's not true. penguins belly flop down snow hills all the time and are able to get back up. that's funny ;)
They fly in California.
You can fly helicopters.
There are many different helicopters. Most small civilian helicopters may fly for about an hour, but large passenger or military helicopters can fly for 6 hours or more.
No