Air flowing over any swept wing tends to move spanwise towards the rearmost end of the wing. On a rearward-swept wing this is outwards towards the tip, while on a forward-swept wing it is inwards towards the root. As a result, the dangerous tip stall condition of a rearward-swept design becomes a safer and more controllable root stall on a forward-swept design. This allows full aileron control despite loss of lift, and also means that drag-inducing leading edge slots or other devices are not required.