Budget airline Ryanair has been told to withdraw an advert featuring a model in schoolgirl-style clothes and a headline "hottest back to school fares".
The Advertising Standards Authority (ASA) said the "irresponsible" image appeared to link teenage girls with sexually provocative behaviour.
The advert shows the model with a bare midriff in a short skirt, tie, shirt and knee-high socks in a classroom.
Ryanair refused to withdraw the image and said the ruling was "censorship".
The advert, which was printed in three newspapers reaching 3.5 million readers - the Herald, Daily Mail and Scottish Daily Mail - publicised flights from £10 one way.