I bought a non-refundable ticket. Can I still get a tax refund?

The price you pay for a flight booking is a net price which, in almost all cases, already includes local taxes. It is only the price before the airport taxes that the airline is in the position to make non-refundable. This means that taxes paid as part of the booking are fully recoverable in all cases of unused tickets, even if the ticket is marketed as being non-refundable.