As, your surgeon and especially your anesthesiologist what you can eat and how long before surgery you can eat. The danger is that your body is asleep and immobile during surgery, so you may choke on your stomach contents if you've eaten too much or eaten too soon before surgery.
Flying on an airline has no effect on breast implants. If you are asking about how long after a surgery before you can fly, that will depend on how healthy you are and how long your recovery takes. You will have to ask your doctor to be sure.