According to a survey, all 40 of the most trusted brands in the United States use blue. This means that blue is not only a color that is easy to remember, but also a color that evokes trust. Therefore, placing brand advertisements on blue airplane seats can help people remember it easily.
This is a general idea about why airplane seats are blue. There are also airlines that use blue airplane seats for different reasons. And as an exception, there are airlines that use red and green airplane seats. Let me end this article by mentioning that