[dogma1138]

since the helipad is usually inside the airports flight area you are already per-cleared at the embarkation point so as long as the helicopter makes no stops on the way you won't have to do anything at the airport.

This is very similar to how private charters operate at commercial airports they have their own security checks which are usually much much more lax than the commercial passengers.

Some airport shuttles (in some countries) also allow you to do a security precheck and to turn in your luggage prior to even reaching the airport.