The British NS class non-rigid airships were the largest and last in a succession of "blimps" that served with the Royal Naval Air Service during World War I; developed from experiences gained with earlier classes to operate off the east coast of Britain on long-range patrols. Despite early problems, examples of the class went on to break all flying records for non-rigid airships, and the type became regarded as the most efficient of its kind.

A blimp (/blɪmp/), or non-rigid airship, is an airship (dirigible) without an internal structural framework or a keel. Unlike semi-rigid and rigid airships, blimps rely on the pressure of the lifting gas inside the envelope and the strength of the envelope itself to maintain their shape. Blimps are known for their use in advertising, surveillance, and as observation platforms due to their maneuverability and steady flight capabilities.