If I ship a box of potato chips to the Philippines by USPS express by aircraft will the bags explode?

I think they leave a bit of extra space in the bag so they can expand, but won't explode. If you are worried about it, put the bag in a larger plastic bag, so that the chips won't go all over if it does pop. However, I doubt it will. Why is your fiance so far away! Perhaps you should deliver them in person. Just kidding! I'm sure they will be fine.

No, they will not. Due to the altitude and the air pressure inside the aircraft, the bags will "bloat" and the air expand in them. This will happen with any type of sealed container. I will usually carry a bottle of water with me and while in the middle of the flight I will take a few drinks from it and then screw the cap back on tight. I can use this to determine when the aircraft begins it's decent prior to the pilots announcing it. Because the air pressure is less higher up, once we start to descend, the air pressure in the plastic bottle is less than that in the airplane and starts to crush the bottle. The further down we go, more pressure is forced on the outside of the bottle and collapses it more. Like wise, since the chips are bagged and sealed at ground level, the air pressure is sealed in them at that time. When it goes up in an aircraft the air inside the bag begins to expand and bloats the bag like a balloon. Again this is due to the pressure up high is less than what was sealed in the bag. Many times on an aircraft I have received a small bag of chips with lunch. No exploding occurs. This same pressure is what causes your ears to "pop" when you ascend and descend.

They will not pop. The plane is pressurized to 8000 ft. I have eaten bags of chips onboard flights before, and they do expand a little bit, but nowhere near popping. The pressure does NOT remain constant as someone said earlier, but the change would not be enough to pop the bag. They will spoil if you pop holes in the bag beforehand, so don't do that, because there isn't even a need for it.

I would suggest packing them tightly with popcorn packing. They probably won't burst because airplanes are pressurized.

They would be carried in a pressurized aircraft so no, they would not explode (unless there was a cabin depressurization).

I sent 10 bags of Humpty Dumpty chips from Maine to California by USPS and most if not all of them popped open

That was so sweet, are you a Filipina?

i had a big bag of lays and it exploded

The cabin pressure of any aircraft will drop when climbing. Even in a pressurized plane the pressure will drop to a pressure altitude of approximately 8000 feet. (that's why you constantly have to pop your ears when climbing or descending. You do that to equalise the pressure in your inner ear with the outside pressure, if you wouldn't do that your eardrum would rip.) The only reason why aircraft are pressurized is because if the pressure altitude is higher than approximately 10000 to 14000 feet (cruising altitudes of passenger jets are mostly way higher than this), the oxygen pressure in the air is not sufficient for humans to breath. By pressurizing an aircraft you make sure that not everybody has to wear oxygen masks during the flight. Although I've never taken a bag of chips on a flight with me, I can imagine that the pressure difference is sufficient for the bag to pop before reaching a cabin altitude of 8000 feet.