Yes, several times. A letter won't do anything for you. The best advice I can give you is to arrive early and proceed through security. Tell staff in the area you have had a hip replacement. You will set off the alarms and they will need to use a wand on you. Note that the person doing the wand will have to be female. If there are no female members of staff available you will need to wait until they find one. Always best to go through security early so you make your flight.Has anyone traveled by air in the US with their new prothesis?