Extended sitting down or inactivity can cause leg swelling. Any time you sit for extended intervals, which include with a plane or in a desk, blood flow slows down, and fluid can accumulate inside the legs. This is often referred to as “sitting illness” or “vacation-similar edema.”   There is https://www.sgvascularctr.com/swollen-leg-why-do-i-have-it-and-what-can-i-do/