The couple, who met nine years ago when ex-Hear'Say singer Shentall was a backing dancer for Steps, are among 11 celebrities training to become airline staff on the ITV2 series.
Shentall insisted that his wife has more of a competitive streak than him, saying: "She thinks she's going to win! You think you're going to beat me. To be fair, I'm laid back so I don't really care [about winning]."
Scott-Lee stated that she felt competing against her husband for a charity prize would benefit their relationship.
"I think it’s healthy to have competition in a relationship," she said. "[We've been together] nearly ten years now so we're doing something right, aren't we?"
The former Steps singer added that she liked the CelebAir staff uniforms because they reminded her of Steps song 'Deeper Shade Of Blue'.
"I feel very comfortable in mine, because I wore something very similar in a Steps video," she said.