My maid will also 放大假返菲律賓 in Dec. I also need to buy her 內陸機票. She said they usually choose 菲航. I guess, the airfare of 菲航 is not expensive. I will compare the price first, if the price is not quite expensive, I will let her 搭菲航.
To my understanding, you don't need to pay for your maid's domestic flights. You only need to buy her an airticket going back to the Philippines/Manila.