Little Boots was furious after she was refused an upgrade on a flight.
The singer - real name Victoria Hesketh - was flying from London to Los Angeles when she was told by staff at Heathrow airport she wouldn't be receiving star treatment for the 11-hour journey.
An onlooker said: "Little Boots wasn't happy. She wanted to fly first class as it was a long flight and wasn't impressed when she was told she couldn't."
Her upset was then increased when she heard a rumour her friends The Saturdays had been moved to upper class on the same flight.
However, band member Frankie Sandford was quick to assure Little Boots they hadn't been given any preferential treatment.
Meanwhile, Little Boots has revealed she sleeps in her make-up.
The 'New In Town' singer often goes to bed without cleansing her skin after a night of partying because she likes the way she looks the next morning.
She said: "Sometimes if you sleep in your make-up it can look quite cool, or you might just look like a dirty stop-out. Many a morning I've still been a bit drunk, I looked in the mirror and thought I looked really nice."