The looped hose method was only of use with large multi crew planes since crew members were required to assist in the hauling in. A modified method known as the probe and drogue system was developed to allow single seat aircraft to be refuelled in the air. With jet fighters suffering from short range there was a need for these to be refuelled in the air and several KB-29Ms were modified to use 'probe-and-drogue' systems, in which the refueling hose has a torus-shaped "para-drogue" attached to the end, and the receiving aircraft has a probe on its nose or wing, which the pilot manoeuvers into the drogue to link the hose.