Spinner is most commonly used as a term for a kind of rolling luggage with four spinning wheels.
In airline parlance, spinner is a term used by flight crew to denote a kind of unwanted passenger. For some, a spinner is one who boards late and doesn’t have a seat assignment or know which seat is theirs, so they “spin around” looking for it.
Another definition in airline parlance states that a spinner is one who is unhappy with their seat assignment, and thus walks down the aisle of the plane looking for a better option, “spinning around” at the very end and making their way back. In whichever case, spinners are all but unwelcome.
For more, see our post on flight jargon and lingo.