My daughter is a flight attendant and is required to wear panty hose and it must be a specific shade, too. One reason is that it looks more professional, something the airlines like to encourage.

In addition, due to spending all their days up in the air and on their feet, it is suggested that they wear compression hose. Not the compression hose you find in a drugstore or department store. It is medical grade hosiery and when prescribed by their doctor, they receive reimbursement through their company's insurance. I don't know the compression ratings off the top of my head but each pair costs around $80.

Flight attendants are more prone to varicose veins due to the higher altitude and the constant changes in air pressure due to multiple take-offs and landings in a day (despite pressurized cabins). E.g., Four short haul flights in a day equals 4 take-offs and 4 landings every day. Over time, the strain on the vascular system can add up, especially if your family's genes predispose you to varicose veins.

Source: https://www.quora.com/Why-are-flight...wear-pantyhose