The Caterpillar Club is an informal association of people who have successfully used a parachute

Parachute

A parachute is a device used to slow the motion of an object through an atmosphere by creating drag, or in the case of ram-air parachutes, aerodynamic lift. Parachutes are usually made out of light, strong cloth, originally silk, now most commonly nylon...

 to bail out of a disabled aircraft. After authentication by the parachute maker, applicants receive a membership certificate and a distinctive lapel pin. It should be absolutely clear that the nationality of the person saving his life by parachute and ownership of the aircraft are not factors in determining qualification for membership; anybody who has saved his life by using a parachute after bailing out of a disabled aircraft is eligible.