“When cabin pressure decreases, the natural air inside the bowel will expand. “And since there is only limited space in the large bowel, it is a natural consequence to fart.” This is also why your ears can pop during a flight, due to the change in pressure.

Leg and foot swelling during air travel is common and typically harmless. The most likely culprit is inactivity during a flight. Sitting with your feet on the floor for a long period causes blood to pool in your leg veins. The position of your legs when you are seated also increases pressure in your leg veins.