This study will determine if newly developed and more standard tests of Eustachian tube function can identify those persons who have ear pain (barotrauma) or develop middle-ear inflammation and/or fluid (barotitis) when they are exposed to rapid changes in air pressure as, for example, during airplane flights or scuba diving. Up to 150 adults and children (10-50 years old) who fly or dive at least 1-2 times and experience ear pain or develop middle-ear fluid during those activities and approximately 60 adults and children who fly or dive but do not experience these problems will undergo Eustachian tube function testing during simulated flight and diving.