Dame Gillian Morgan, 65, noticed the stickers following her flight to Bristol from Paphos, Cyprus.
She saw stewardesses handing out the stickers to children on board the plane.
In an interview with Metro, Dame Morgan said it was “deeply sexist” and was “absolutely sure” it was deliberate to hand stickers by gender.
“The stickers were gender neutral but it’s the way that they were handed out that makes it complicated,” she told the Metro.
“I was with my great-niece and my great-nephew and of the two of them, she’s going to be the pilot, he’s going to be the cabin crew,” Dame Morgan said.
“I just think it’s a shame. TUI were trying, I think, to do the right thing but fundamentally missed the point.
“There must have been a way of doing it with a bit more thought. I was quite upset by it really.”
Other passengers on flights in May and July also criticised TUI for handing out the stickers.
One Twitter user said: “@TUIUK your cabin crew today chose ‘future tui cabin crew’ stickers for the girls and ‘future pilot’ for the boys, no female pilots then?”
Another said: “Lovely touch by @TUIUK flying out of Corfu Friday by giving children TUI stickers and activity sheet… not so lovely that all the boys were given ‘future pilot’ stickers and the girls ‘future cabin crew’?! Sexist much?”
A TUI UK spokesperson in an email to Sky News said: “We’re sorry to hear a small number of customers have been upset by this.
“We think it has just been a simple mix-up since our future pilot and cabin crew stickers are designed for use for any child regardless of gender.
“The stickers are part of our activity packs which are intended to be used by crew to interact, engage with and create special moments for our customers on their holiday.
“The feedback we’ve had so far this summer has been overwhelmingly positive.
“Children fall in love with flying when they go on their holidays with us and we want to encourage their dreams of becoming future pilots and crew members.”