London (CNN) — An airline has apologized to a 21-year-old woman for threatening to offload her from a flight for wearing "inappropriate" attire.

Emily O'Connor, who was traveling on a Thomas Cook Airlines flight from the UK's Birmingham Airport to Tenerife in the Canary Islands on March 2, said the cabin crew told her that her clothing was "causing offense." Her outfit consisted of a crop top and high-waisted pants.

"Flying from Birmingham to Tenerife, Thomas Cook told me that they were going to remove me from the flight if I didn't 'cover up' as I was 'causing offence' and was 'inappropriate,' " she wrote on Twitter. "They had four flight staff around me to get my luggage to take me off the plane."

She said she had worn the outfit through the airport and was only told to cover up upon entering the plane by the cabin crew.

A spokesman for the airline appologized for the incident and said staff 'could have handled the situation better.' Sean Gallup/Getty Images Europe/Getty Images

O'Connor said she stood up to ask fellow passengers whether they were offended by her outfit, and received no response.

She said the flight manager, along with four other staff, then told her to put on a jacket or be removed from the plane. "The manager then went to get my bag to remove me from the flight," she wrote on Twitter.

O'Connor was given a jacket by her cousin, who was seated at the front of the plane, and was not watched until she had physically put it on, she said.

"They made comments over the speaker about the situation and left me shaking and upset on my own," she wrote.

CNN has contacted O'Connor for comment.

Thomas Cook Airlines said it has apologized to O'Connor and the airline's cabin services director had spoken to her "to find out more information" about the incident.

"We are sorry that we upset Ms O'Connor," the airline said in a statement seen by CNN. "It's clear we could have handled the situation better.

"In common with most airlines we have an appropriate attire policy. This applies equally to men and women of all ages without discrimination. Our crews have the difficult task of implementing that policy and don't always get it right," the airline added.