While booking a flight from Santiago, Chile to La Paz, Bolivia I have to confirm the following dialog on the skyairline.cl website:
The airport boarding fee in La Paz is not included in your airline ticket and has to be paid at the La Paz airport prior boarding your flight
I have read and understood this important information.
I read but have not understood this important information. What is this fee about? When do I have to pay it (I assume only at departure)? And how much is it?