No airport taxes from Manila. That stopped a few years ago ( most recently there Apr & Oct 2019).
Other airports, Cebu, Clarke etc set their own and as Ginner said, cash.
In fact, this applies to most of Philipines; apart from the big intenational hotels many of the resprts / dive operators prefer cash and may apply a surcharge for cards or offer a discount for cash with both USD and Peso accepted most places.
If you pay cash and no discount is offered, then ask, you may get 5%.
In the smaller towns / resorts there may be no bank or ATM so check with the hotel / shop ahead and carry cash.