The helicopter is an interesting object in our culture. Originally, it was thought that the helicopter would replace the car someday. However, prices never came down, leaving the helicopter as an icon of wealth or authority. Since the Vietnam War, helicopters have become more associated with conflict than commuting.
To dream of a helicopter probably means that you envision yourself in a situation of potential hazard or needing to be "whisked away" from your present circumstances. The former would be expressed in a helicopter as a means of escape. The latter equates images of romance and wealth.