US Airways has apologised after a pornographic tweet it sent to a customer went viral.

We apologize for an inappropriate image recently shared as a link in one of our responses. We’ve removed the tweet and are investigating.

— US Airways (@USAirways) April 14, 2014

The customer – known as “Alex” was sent a pornographic image after she complained about her flight to Portland, Oregon being delayed.

On Monday the airline responded courteously but inadvertently attached a pornographic image.

I knew US Airways left Star Alliance at the end of March, but I didn’t realize just how different a business model they were pursuing…

— Ben Rothenberg (@BenRothenberg) April 14, 2014

US Airways quickly removed the tweet but it was still online long enough for hundreds of Twitter users to save the offending image.

The airline has since apologised for the tweet.

“We apologise for an inappropriate image recently shared as a link in one of our responses. We’ve removed the tweet and are investigating,” it said on its Twitter feed.

Either someone at US Airways is terrible at doing their job or incredible at quitting their job.

— CC:Indecision (@indecision) April 14, 2014

Spokesman Matt Miller said the photo was sent to the @USAirways account from an unidentified individual.

“Our investigation has determined that the image was initially posted to our Twitter feed by another user. We captured the tweet to flag it as inappropriate. Unfortunately the image was inadvertently included in a response to a customer”. 

Big thanks to @USAirways for finally giving us a satisfying ending to LOST.

— Jessica Weil (@Jessica731) April 14, 2014