Airline tickets come with a luggage allowance - some with zero allowance - and this is checked when you check-in your bag with AirPortr.
An excess charge is a broad term for when:
- You have more items than you have paid for; or
- An individual item is heavier than you have paid for;
- An item is oversized and the airline policy charges differently for this (for instance skis).
Always check with your airline for their policy on excess charges. AirPortr will simply pass on the charge from the airline to you.