When layover flights are booked with the same airline, your baggage will be automatically transferred through to your final destination. However, if the two flights are with different airlines, you may have to claim and re-check your baggage during your layover.

Whether you need to collect your bags depends on your itinerary, the country you are transiting through, and how your tickets were booked. If you are on a single ticket (one booking reference) with partner airlines, your bags are usually "checked through" to your final destination. However, a major exception is the United States and Canada; if your first point of entry into the U.S. is a layover city (e.g., flying London to JFK to LAX), you must collect your bags after immigration, clear customs with them, and then drop them at a "connecting flights" belt. In most European and Asian hubs like Dubai or Singapore, you generally do not see your bags during a connection. If you have booked two separate tickets (self-transfer), you will always have to collect your luggage, exit the secure area, and check in again with the second airline.