Add checked baggage online before the flight, never at the counter.

Airline fee schedules are tiered: cheapest at booking, more later online, most expensive at the airport.

Decide about luggage the night before and pay at the counter.

Decide baggage needs when booking. If you must add later, do it via the airline's app or website before online check-in closes.

1. STEP 1Check the airline's published baggage fee schedule.
2. STEP 2Add baggage at booking, or via 'Manage booking' well before the flight.
3. STEP 3Weigh your bag at home to avoid excess-weight fees.

You’ll need: Airline app or website account

• ✓Any flight with checked luggage on a low-cost carrier.

• ✗Full-service fares that include baggage.

• !Fee tiers vary by airline and route.