In-flight cabin environment differs to some extent from what your body is used to on the surface of the Earth. As altitude rises so the atmospheric pressure decreases.

Although this is partially compensated for by cabin pressurisation, gases inside your body will nevertheless expand and sometimes cause symptoms such as ear plopping or bowel distension.

Contrarily to some passengers with severe, unstable cardiovascular problems, normal, healthy people are not affected by speed variations of commercial aircraft during take-off and landing manoeuvres.

At normal commercial aircraft cabin cruising altitudes there is no need to supply passengers with oxygen.

Inside commercial aircraft cabins, atmospheric pressure corresponds roughly to the top of a 2000-2500 meter high mountain, to which healthy people naturally adapt.