We recommend avoiding airplane travel for four weeks after breast augmentation if the implant have been placed under the muscle.
This is due to the variety of motions that are performed before, during and after a flight that may demand quite a lot of the pectoralis muscle while still weak and may lead to slight or significant tears in the muscle structure.
Think of how often you load 20lbs or more over your head into a bin, squeeze in strange seats and pull a trolley for a significant distance? All these actions affect your pec and may cause problems in the area.
Likely the swelling is caused by a temporary cramping or minor stretch-tear in the muscle fibers. However, it is important to be evaluated promptly by an expert plastic surgeon to exclude more extensive damage.