Air travel operates under a set of rules that few passengers know and that airline agents often will not volunteer. This article explains what an airline actually owes when a flight is cancelled, when a passenger is involuntarily denied boarding, when bags are lost or damaged, and when an aircraft sits on the tarmac for hours. It distinguishes the legal entitlements — which are narrower than most people assume in some areas and far stronger than most people assume in others — from the goodwill compensation an airline may offer to make a problem go away. Separate parts cover the contract of carriage as the governing document, the federal preemption doctrine that bars most state-law claims against airlines, international carriage rules for baggage and delay, disability access requirements, and the credit card chargeback right that is frequently the fastest remedy available. Later parts cover rental cars, cruises, hotels, and third-party booking sites, where the rules are different and generally less favorable. Examples run throughout.