The smell of the fuel, the 'tick... tick... tick...' of the starter, the whine of the turbine, the 'magic carpet' ride as you lift into the hover, the fact that only a small number of people get to enjoy the feeling of flying a helicopter - and they had to work hard for the privelege, the views, the freedom, the fact you have to concentrate, the look on pax' faces when they've had the experience of a lifetime, the physics, the noise, the smell! I just love it all!!
TTB