Police spokesman Roland Ekkers said the girl, who has not been identified for privacy reasons, turned herself in to Rotterdam police in the company of a parent Monday and is now being interrogated.
The tweet posted Sunday said it came from an al-Qaida member in Afghanistan named Ibrahim and threatened to "do something really big on June 1." But the account's handle came with the nickname "Sarah" and a profile image of a young woman.
Apologetic tweets were posted to the account after the airline replied it was taking the threat seriously and calling in law enforcement.
Ekkers said the motive for the tweet is not yet known.