According to the DOT, “once an airline determines that your bag is lost, the airline is responsible for compensating you for your bags' contents – subject to depreciation and maximum liability limits.”

Under the 2026 Montreal Convention and updated DOT regulations, the airline you last flew with is legally responsible for your lost luggage, even if multiple carriers or airports were involved in the journey. If your bag fails to appear on the carousel, you must file a Property Irregularity Report (PIR) before leaving the airport. This document is your proof of claim. In 2026, domestic US regulations mandate that airlines compensate passengers up to $4,700 for lost or delayed bags, while international limits hover around $1,700 to $2,000 (depending on current SDR exchange rates). The airline is also responsible for reimbursing "reasonable expenses"—such as toiletries and basic clothing—while you wait. Note that while the airport handles the physical logistics of the baggage system, they have no direct liability to the passenger; your contract of carriage is with the airline, and they are the entity that must pay the claim.