On a normal day on ground level we break wind around 10 times a day and expel about a litre of gas however when we are on a plane the figures significantly increase.
The reason why we break wind is because gasses are brewed from food that has failed to be absorbed by the gut and produce nitrogen, carbon dioxide and hydrogen. There is a scientific reason as to why we feel bloated when we are flying.
Clinical professor Jacob Rosenberg says that, "The pressure drops and the air must expand into more space."
That one litre of gas inside us now needs to fill a 30% bigger volume, which leads to bloating. More than 60% of pilots report regular abdominal bloating, and 60% of pilots experience the uncomfortable feeling in the abdominal.