It regularly comes up as one of the top pet hates of frequent flyers - sitting next to unhappy children or crying babies on flights. But for one business man, taking a seat next to a little autistic girl called Kate began a beautiful friendship and made her family's day.
So much so that mum Shanell Mouland, who runs an autism support blog called Go Team Kate, wrote an open letter to the stranger, thanking him for his reaction to her daughter.
She starts the letter Dear 'Daddy', after Kate called him that for the entire flight they sat next to each other - and he didn't correct her.
"...I sat Kate in the middle seat knowing full well that there would be a stranger sitting next to her for the duration of this flight. I had to make a quick decision and based on her obsession with opening and closing the window shade I figured she might be less of a distraction if she sat in the middle.
"For a fleeting moment I thought we might have a free seat beside us and then you walked up and sat down with your briefcase and your important documents and I had a vision of Kate pouring her water all over your multi-million dollar contracts, or house deeds, or whatever it was you held. The moment you sat down, Kate started to rub your arm. Your jacket was soft and she liked the feel of it. You smiled at her and she said: "Hi, Daddy, that's my mom." Then she had you."
[Raising an autistic and epileptic daughter]
[Why siblings were the best thing I could have given my Asperger's son]
She continues: "You could have shifted uncomfortably in your seat. You could have ignored her. You could have given me that 'smile' that I despise because it means; 'manage your child please.' You did none of that.
"You engaged Kate in conversation and you asked her questions about her turtles."
And she explains how this kind stranger even stayed calm under the pressure of Kate struggling with being on the plane after so long.
"Not long before we landed Kate had reached her limit. She screamed to have her seatbelt off, she screamed for me to open the plane door and she cried repeating, "Plane is cwosed (closed)" over and over. You tried to redirect her attention to her toys. She was already too far gone at this point, but the fact that you tried to help your new little friend made me emotional."
[How my family works with my autistic child]
[The rise of whopper babies]
And she finishes with a heartfelt 'thank you' to the man who made his daughter's flight so much more enjoyable for all of them. What a guy.
"So, thank you. Thank you for not making me repeat those awful apologetic sentences that I so often say in public. Thank you for entertaining Kate so much that she had her most successful plane ride, yet. And, thank you for putting your papers away and playing turtles with our girl."