If you have swollen feet on plane, how do you get them back to normal in hours?

Try laying down: Flat, prop feet up on players......So they are above heart level.

Move around: Prior to flying, consider getting compression hose to wear on board. Because of the prolonged sitting and cramped space, the legs/ankles/feet remain still and are subject to swelling due to dependent (gravity) positioning. If possible, sit in an aisle seat and/or bulkhead so you have more room and get up and move during the flight to get the blood/fluids in your legs circulating.