The complainant said the ads were "misleading as it strongly implied the sale was an Easter sale".
The airline defended the ads and said it did not believe they breached the codes of practice.
The ASA said despite the travel periods being included in the advertisement, the ads were still misleading. It ordered Jetstar to take down the ads.
Meanwhile, the ASA has ruled that a "tasteless" ad that used a fictional image of "the Elephant Man" Joseph Merrick, who suffers from severe deformities, "did not meet the threshold to cause serious or widespread offence".
Art supplies company Paper Tree used the image on a billboard ad with the words "extreme makeover - new look Paper Tree".
The complainant to the ASA said the image was "extremely offensive" and "mocks an actual person who suffers from a devastating medical condition".
The ASA said "the advertiser had attempted to use a level of humour and link the image to the notion of an extreme makeover".
"While the [ASA] chairman was sensitive to the particular situation of the complainant, she held that the advertisement, while tasteless, did not meet the threshold to cause serious or widespread offence."