Although the stressful process of air travel can often bring out the worst in people, it seems like it can also bring a whole lot of kindness. On December 6th, a passenger on an American Airlines flight from Orlando to Philadelphia volunteered to give up his first-class seat to a mother traveling with her 11-month-old daughter, who was hooked up to an oxygen machine. Kelsey Zwick and Lucy, her daughter, were heading to Philadelphia so Lucy could receive treatment for a chronic lung disease at the Children’s Hospital of Philadelphia.

When the mother and daughter took their original seats, a flight attendant promptly informed them that a man in first class had offered to switch seats with her. Although Zwick didn’t know the man’s identity, she later posted on Facebook, “To the man in 2D…You were giving up your comfortable, first-class seat to us. Not able to hold back tears, I cried my way up the aisle while my daughter Lucy laughed! She felt it in her bones too…real, pure, goodness.”

The first-class seat made Lucy’s journey to Philadelphia far more comfortable. She uses her oxygen tank while flying due to low cabin pressure, and the first-class seat gave her extra room for the apparatus and the pair of travelers.

The gesture of kindness came at exactly the right time for Zwick, who has struggled in the midst of her daughter’s treatments and hospital visits the past two years. “It wasn’t just the seat,” she told Yahoo. “It was the culmination of everything we’ve been through.”

In Zwick’s Facebook post, she added that the act of kindness reminded her of “how much good there is in this world. I can’t wait to tell Lucy someday. In the meantime…we will pay it forward.”

Through the magic of social media, the post did reach the generous first-class traveler. As it turns out, it was the man’s birthday. “I am so glad we were on the same flight,” he told her.

H/T: Travel & Leisure