There are a number of different synonyms for the term "airplane seat attachment." Some of the most common ones include "airplane seat belt," which is often used to describe the safety harness that passengers wear during takeoff and landing. Other common synonyms include "airplane restraint" and "airplane harness," both of which can refer to any device that helps keep passengers securely in their seats. Additionally, some people may use the term "airplane tether" to describe any type of attachment that is used to keep a person connected to their seat while flying. Regardless of the exact terminology used, all of these devices are designed for one primary goal: to keep passengers safe and secure throughout their flight.