How Fly navy sail army walk sideways?

Answer 1

While some of the explanations below are derived from or purported to be the "official" version the RAF have been named "crabs" due to the fact that they have no limit to the number of sideways paces they can do as a drill movement. While army and navy have a fixed limit of sideways paces the RAF can actually march the entire width of a parade ground sideways.

Once upon a time, the RAF flew Spitfires with tail wheels near the tail and huge Merlin engines at the front. This meant that during taxiing, all they could see to the front was an enormous engine. In order to see what was in front of them, they had to look over the side and zigzag, thus they'd be moving sideways. On landing, they would sideslip to lose height.

Because of airfield security, the only time land-locked mortals got to see the RAF anywhere near close up was during landing, take-off and taxiing, when they were moving sideways. Since only crabs walk sideways, clearly the RAF was staffed by crabs.

Coupled with the fact that the Fleet Air Arm attracted all the best pilots and the Army always won inter-service regattas, a once popular forces T-shirt logo read: 'Fly Navy.Sail Army. Walk Sideways!'