If an airline cancels one leg of a multi-segment flight in 2026, your rights depend on whether the trip was booked as a single contract (one PNR) or separate tickets. Under a single contract, the airline is legally obligated to rebook you on the next available flight to your final destination at no extra cost or provide a full refund for the unused portion. In regions like the EU (under EC 261/2004) or India (under revised DGCA norms), you may also be entitled to financial compensation ranging from €250 to €600, depending on the distance and the delay's duration, unless the cancellation was due to "extraordinary circumstances." Furthermore, the airline must provide "Duty of Care," which includes complimentary meals, communication, and hotel accommodation if the rebooked flight requires an overnight stay. If you booked separate tickets (often called "self-transfer"), the second airline is not responsible for the first one's delay, and you could lose your subsequent flight entirely without a refund. Always aim for a single booking to ensure the airline bears the responsibility for "domino effect" disruptions.