As an expert builder using the grace that God gave me, I laid the foundation, and someone else is building on it. But each person must be careful how he builds on it. According to the grace of God given to me, like a skilled master-builder I laid a foundation, but someone else builds on it.
The most-advanced helicopters can fly up to 300 miles before having to refuel. How long any particular helicopter can fly without refueling depends on the size, weight and age of the helicopter.
The main limitation of the helicopter is its low speed. There are several reasons a helicopter cannot fly as fast as a fixed-wing aircraft. When the helicopter is hovering, the outer tips of the rotor travel at a speed determined by the length of the blade and the rotational speed.