The billboard was advertising Air NZ's cheap seat site, Grabaseat.
Stop Demand Foundation, which campaigns against sexual violence and sex abuse, wanted the billboard taken down and an apology from Air NZ.
"Yes, most of us like 'edgy and provocative'," said Stop Demand founder Denise Ritchie.
"Most of us don't like, or accept, 'sexist and ageist'. Most of us know the difference. Apparently you do not," she said in an email to Air NZ.
Grabaseat manager Duane Perrott said the slogan was an entry in a competition from a Wellington resident whose grandmother lived in Nelson.
"What this person thought was funny, as did many others, clearly didn't resonate with some individuals today and Grabaseat will be removing the billboard shortly," he said.
"We apologise if any offence was caused."
Grabaseat brand manager Russell Long said in an earlier email to Stop Demand that the intention was to be irreverent and provocative, not "overtly offensive".
Family First had also called for the withdrawal of the billboard, saying it insulted grandparents and would be seen by children.
