Car seat. The seat was supposedly designed to be used on planes. They spent a while trying to install this seat and when it was finally done a flight attendant noticed it and made them remove it because it was blocking the seat in front of them from reclining. So they had to undo the whole operation. To make matters worse, since their infant was a ticketed passenger, it could not be on their laps during takeoff and landing. The whole thing was such a debacle.