What happens next depends primarily on whether your flights were on a single booking or separate tickets. If you booked a through-ticket and the airline caused the delay (due to mechanical issues or late arrival), they are legally obligated to rebook you on the next available flight at no extra cost. In regions like the UK and EU (under EC 261), you may also be entitled to "duty of care" benefits, including meal vouchers and hotel accommodation if the wait is overnight. If you miss a connection due to your own delay or if you booked separate tickets (a "self-transfer"), the airline is generally not responsible for rebooking you for free, and you may have to purchase a new seat at current market prices. In all cases, your first step should be to head to the airline's transit desk or use their mobile app to see your rebooking options. If you have checked luggage, the airline will typically track it and either hold it at the final destination or reroute it to your new flight.