To claim senior citizen discounts on airfare, you need to show your senior citizen ID when purchasing your ticket. Most airlines in the Philippines offer a 20% discount on domestic flights for seniors. It's best to check with the airline directly, as some may have specific processes for applying the discount online or at the ticket counter. Additionally, make sure to book your flight in advance to ensure availability and avoid any last-minute issues. For the latest information, visit the airline's website or contact their customer service.