A passenger on the flight from Newark to Orlando said when boarding the flight, she noticed people consistently passing up two rows of seats half-way down the plane.
"As I got closer, I found one row with a father and his 18-month-old daughter and the other row with his wife and the daughter's twin," Christina Galese explained on Facebook.
Galese continued: "Because I don't mind children (and knew I had my headphones for later on, just in case), I opted for the window seat next to the father and one of the twins.
"The rest of the passengers boarded and the middle seat in between us was eventually occupied.
"Before the flight took off, the parents passed around these goodie bags to the other passengers around them.
"Such a thoughtful, simple act of kindness that I am so happy to have experienced."
Galese uploaded a photo of a clear plastic bag with chocolates and snacks inside.
Inside there was also a note, which read: "Hello! Our names are Ashley and Abbey. We're twins, we just turned 18 months is this is our first time on an airplane.
"We are heading to see grandma, grandpa and mummy and daddy said something about a mouse.
"We'll try to keep our cool, but incase we decide to get crazy, we've provided a sweet treat and some ear plugs for your enjoyment.
"Thank you for understanding and enjoy your flight."
Galese said the twins were "the most adorable and well-behaved little girls ever".
She added: "I never had to reach for the ear plugs once - the only time I opened the bag was to have a piece of chocolate.
"I hope this family has the most wonderful vacation."
The story, shared on Love What Matters Facebook page on 4 July, was shared 1,600 times in 19 hours.
Parents commenting on the post agreed the sentiment was sweet, but felt mums and dads shouldn't have to apologise for their children.
"This is nice, but kids are kids and I think if parents are doing their best to calm their child down on a flight, they shouldn't apologise," one person commented.
Another wrote: "This is very considerate of the parents and very sweet however I wish society would get over this whole thing with kids on flights.
"Children will be children. They will whine, cry and fuss - especially when tired.
"We were all fussy kids at one point or another in our life, best we remember where we came from and lend a hand to help a parent or cheer up a child instead of complaint, ridicule, and scoffing."