Airlines are not legally required to wait for connecting passengers, and in 2026, the decision is almost entirely based on operational mathematics. An airline's primary goal is to maintain its "On-Time Performance" (OTP), as a 15-minute delay can cause a "ripple effect" that disrupts dozens of subsequent flights and crew schedules, potentially costing the company thousands in landing fee penalties and fuel. However, an airline might wait if the number of connecting passengers is high (e.g., 20+ people coming from a single delayed flight), if it is the last flight of the day, or if the "cost" of rebooking everyone on other carriers exceeds the cost of the delay. Pilots and gate agents use real-time software to determine if a "hold" is viable. If you miss your connection due to an airline-controlled delay, their legal obligation in 2026 is generally to rebook you on the next available flight and provide "Duty of Care" (food and hotel) if the wait is overnight, but they are rarely willing to delay 200 other passengers to save one or two latecomers.