Who pays for the transfer between 2 airports?
Santa, if you're lucky! If not, we're sorry to burst your bubble, but a transfer between 2 airports is never included in the price of a flight.
For example: you leave Marseille and arrive at Orly airport in Paris, then you take a connecting flight to New York but from Roissy Charles de Gaulle airport. The transfer between Orly and Charles de Gaulle is never included in the price of a flight. So you have to pay the transportation costs (taxi, bus, train, etc.) yourself.
To find out how to get from one airport to the other, click here