Overbooking — Overbooking / Denied Boarding

Why Airlines Overbook in the First Place

Airlines routinely sell more tickets on a flight than the aircraft has seats, on the near-certain expectation — based on historical data for that specific route and time — that some percentage of booked passengers simply won't show up, whether from missed connections, changed plans, or no-shows on a fully refundable or flexible fare. Done well, overbooking fills seats that would otherwise fly empty and lowers fares for everyone by improving the airline's overall revenue per flight; done poorly, or when an unusually high number of booked passengers actually do show up, it results in more confirmed passengers at the gate than the aircraft can carry — a situation airlines have to resolve before departure.

Voluntary Before Involuntary

When a flight is oversold, airlines are required (and in any case strongly incentivised) to first ask for volunteers — passengers willing to give up their seat in exchange for compensation, typically a travel voucher, cash, or both, along with rebooking on a later flight. Only if too few volunteers come forward does an airline move to involuntary denied boarding, selecting passengers to be bumped against their will, usually based on factors like check-in time, fare class, or loyalty status set out in the airline's own policy. Passengers who are denied boarding involuntarily are entitled to statutory compensation in most major jurisdictions — a right that exists specifically to make involuntary bumping costly enough that airlines have a strong incentive to avoid it and to make volunteer offers generous enough to work.

What Compensation Actually Looks Like

Under EU Regulation 261/2004, involuntary denied boarding compensation ranges from €250 for flights of 1,500 km or less, up to €400 for flights between 1,500–3,500 km (or any intra-EU flight over 1,500 km), up to €600 for flights over 3,500 km — payable in addition to a refund or rebooking, and independent of the fare originally paid. The United States has its own separate compensation framework under Department of Transportation rules, and most other major aviation markets have adopted broadly comparable passenger-protection regimes, though the exact figures and mechanics vary by jurisdiction.

Denied Boarding vs a Cancelled or Delayed Flight

Denied boarding is a distinct category from a delayed or cancelled flight, even though it can feel similar to an affected passenger and often triggers a broadly comparable compensation right — the key distinguishing fact is that the flight itself departs on schedule, and the passenger specifically wasn't allowed on it because more people held valid tickets than there were seats, rather than the flight not operating at all.