The primary legal framework for passenger rights in Europe is Regulation (EC) No 261/2004. This regulation dictates that if you are "denied boarding" against your will—most commonly due to an overbooked flight—the airline is legally obligated to provide you with three things: Choice, Care, and Compensation. First, they must offer you a choice between a full refund of your ticket or an alternative flight to your destination at the earliest opportunity. Second, they must provide "duty of care," which includes free meals, refreshments, and hotel accommodation (plus transport) if an overnight stay is required. Finally, they must pay you fixed financial compensation, which ranges from €250 to €600 depending on the distance of the flight. This compensation is mandatory unless the airline can prove you were denied boarding for "reasonable grounds" such as health, safety, or inadequate travel documents. It is important to note that these rights apply to all flights departing from an EU/UK airport, or flights arriving in the EU/UK if operated by an EU/UK-based airline.