The wingsuit flier enters freefall wearing both a wingsuit and parachute equipment. Exiting an aircraft in a wingsuit requires skilled techniques that differ depending on the location and size of the aircraft door. These techniques include the orientation relative to the aircraft and the airflow while exiting, and the way in which the flier will spread his legs and arms at the proper time so as not to hit the aircraft or become unstable in the relative wind. The wingsuit will immediately start to fly upon exiting the aircraft in the relative wind generated by the forward speed of the aircraft. Exiting from a BASE jumping site, such as a cliff, or exiting from a helicopter, a paraglider, or a hot air balloon, is fundamentally different from exiting a moving aircraft, as the initial airspeed upon exit is absent. In these situations, a vertical drop using the forces of gravity to accelerate is required to generate the airspeed that the wingsuit can then convert to lift.