CFR › Title 14 › Part 252Part 252 — Smoking Aboard Aircraft§ 252.1— Purpose.§ 252.2— Applicability.§ 252.3— Definitions.§ 252.4— Smoking ban: air carriers.§ 252.5— Smoking ban: foreign air carriers.§ 252.8— Extent of smoking restrictions.§ 252.9— Ventilation systems.§ 252.11— Aircraft on the ground.§ 252.17— Enforcement.