Flying in the Philippines is blessed with its own idiosyncrasies that may both frustrate and delight you:

1. You won’t be allowed to board the plane to arrive in the Philippines unless you have a flight out within the 30 days allowed for a tourist visa. Keep this in mind as you may have to show proof of your ticket. Luckily flights within Asia can be quite cheap and short so leaving the country to renew your 30 days can be relatively easy. Don’t forget to check which countries require a visa application ahead of arrival (e.g. Vietnam for Australians!)
2. Arriving at Nino Aquino International Airport Manila- the airport staff should be congratulated as they tried to ensure everyone was moved through the passport check as quickly as possible. Foreigners were moved to the lines allocated for locals and specials needs to reduce waiting times (I really appreciate this having waited at the Heathrow foreign passport line for 3 hours). When arriving from South Korea, there were no lines and we walked virtually straight through.
3. There are many many lines… Lines are an undesirable feature of every airport but the Philippines has more than usual. There is a line to get into the terminal complete with baggage scan and check of ID and ticket (it can look intimidating but moved fairly quickly in our experience). There is a line to get to the check in counter. There are lines to get through security; separate ones usually for men and women. There are lines to get into the toilet (which often are grossly under-catered for the airports on the Islands — think 2 cubicles for multiple planes arriving). Pushing in seems to be common place (weng weng) and you will find there will be lines forming in all directions to board the plane. At every turn people will be looking to jump the queue and push ahead of you. Your expectation of doing a quick bag drop may not be reality even if you have checked in online.
4. Regardless of domestic or international, it is a good idea to get there quite early. Boarding will often be advised as at least an hour before take-off for both. Local Filipinos recommended at least 3 hours before and allowing extra for traffic getting to the airport, but this was excessive for most of our flights. I will note that a lot of our flights were very early (7am takeoff) and we were not flying on the weekend.
5. Terminal 4 in Manila was far more disorganised and testing of your patience than the international terminals. We were held up for a long time in the check in queue by passengers who failed to understand baggage allowances and either argued with the staff or sorted through their bags. Once through security, all passengers are in restricted to one waiting room. Food choices are extremely limited unless you want donuts or similar. ATMs were not working for international cards.
6. Dive straight into a good book, listen to music or watch your iPad as it can take a really long time between boarding and take-off. Passengers attempting to sit in seats other than what is on their boarding pass is common place and can take forever for the poor flight attendants to sort out.
7. Baggage : The airlines we flew (Cebu, Air Asia) did not have limits on the number of bags you took, as long as they were under the total weight limit. We didn’t experience any checking of carry on in terms of weight or size, however did see a couple get pulled up in South Korea when attempting to board the plane.
8. Air Asia- expect to pay for EVERYTHING. They would not even give us a glass of water even on a 4 hour flight (We can’t believe that is legal!). Their menu was surprisingly quite good and reasonably priced (hot meals for only ~ AU$6), however there were many items unavailable as is common in the Philippines.