The airline, which has sponsorship arrangements with England Rugby, sent good luck to England via Twitter on Saturday morning ahead of the Fall Countries Cup match against Wales in Lannell.
The tweet, which was later deleted, read, “Good luck to the England rugby team against Wales today.”
The news, which also included a short video, annoyed many Wales fans as they voiced their displeasure on social media.
Welsh Health Minister Vaughan Ketting tweeted: “3m + is a good way to harass customers.”
Labor MP Chris Bryant described the airline as “full divots” and added: “How right is this?”
Welsh BBC news anchor How Edwards joked: “I like @easyJet.”
Meanwhile, the phrase “English Airways” became popular on Twitter, with some Wales fans suggesting the plane be renamed.
One fan tweeted: “Sorry ??? I’m taking it, are you renaming yourself ‘English Airways’? WTF?”
Yes Simru, a campaigner for Welsh independence, tweeted: “To be clear, even if Wales becomes independent, it will remain part of the British Isles.
“Your brand is not ‘UK Airways’, it is ‘British Airways.’
“Regardless, we have this unequal, broken ‘union.”
BA, the official airline partner of England rugby, has apologized for “offside off” with the news.
A statement from the airline read: “We are proud supporters of England rugby, but on this occasion we accidentally went offside, and we apologize for that.”