"Put a f--ing jacket on".
She said: "Let's get a few facts straight".
In an interview with The Sun, O'Connor called the incident 'the most sexist, misogynistic, embarrassing experience of my life'.
Thomas Cook has since apologised to Ms O'Connor, saying "it's clear we could have handled the situation better".
Later on, a spokesperson of Thomas Cook airlines apologized to the woman for their behavior.
"The staff said nothing to him", she wrote.
Her posts about the incident, including a photograph of the outfit in question, quickly went viral, as users weighed in on whether the crew were right to demand she cover up.
The 21-year-old took to Twitter to share a photo of the outfit she was wearing, which consisted of an orange pair of pants and a black strappy bralet.
Responding to a tweet saying it was unsuitable to wear underwear on planes, Miss O'Connor said she had bought the item in the "summer tops" section of Zara a year ago.
"They announced that I was offensive and inappropriate in front of the whole flight". She wrote, "I informed the staff that there is no "appropriate wear" policy stipulated online". The passenger claims flight attendants repeatedly asked her to put more clothes on.
Elon Musk shoots down USA regulator's complaint about his Tesla tweet
However, the US-firm has since announced plans to reverse the decision that would close the majority of its 378 stores globally. Tesla has been showing the base Model 3 to be dependent on the lowering of the company's retail costs.
When O'Connor refused to change, she says a manager left to get her bag in order to remove her from the flight.
"They had four flight staff around me to get my luggage to take me off the plane".
Although her cousin gave her a jacket to wear for the flight, O'Connor said the staff did leave until she "physically put it on".
A University of Birmingham student has described her experience onboard a Thomas Cook flight which saw her asked to cover up more, despite apparently not offending anyone. Reportedly neither airport security nor Thomas Cook boarding crew addressed O'Connor's attire.
She also did a poll on her account see what the public thought.
The airline has now apologised for how its staff behaved.
Emily added: "There was a man behind me wearing a vest top and a pair of shorts, and I was thinking to myself, I'm getting targeted, and said that my shoulders and arms are out, when a gentleman is in the exact same situation". We'll continue calling it out until airlines realise policing women's clothing is unacceptable. A man then shouted "Shut up you pathetic woman".
"Our crews have the hard task of implementing that policy and don't always get it right".
Thomas Cook's "appropriate attire" policy is stated in the in-flight magazine.