The most common complaint among those surveyed is cabin noise. : Jeffrey Greenberg/Universal Images Group via Getty Images 42% of US survey respondents said flight etiquette has worsened in the past five years. The most common complaint among respondents related to in-cabin noise. The survey follows US Secretary of Transportation Sean Duffy's criticism of some flight behavior. From seat-reclining disputes to disagreements over when it's OK to switch seats, many Americans say airline etiquet...