P.L. Travers never did warm up to the song "Let's Go Fly a Kite" as depicted in this movie. According to Richard M. Sherman, it was "Feed the Birds" that won her over.
The audiotapes of the working sessions between the real P.L. Travers and Walt Disney's team amounted to thirty-nine hours, to all of which screenwriter Kelly Marcel, and later Tom Hanks and Emma Thompson, had access. Thompson said she listened to all of them in preparation for her role, and that the experience was "like being poked in the ear with hot forks."
According to the book The Secret Life of Mary Poppins, in a rare 1977 interview, P.L. Travers commented on the legacy of the movie, Mary Poppins (1964): "I've seen it once or twice, and I've learned to live with it. It's glamorous and it's a good film on its own level, but I don't think it is very like my books."
Walt Disney hid his smoking habit from the public, especially children, fearing it would tarnish his studio's family-friendly image. Tom Hanks wanted his portrayal to be accurate, so he lobbied to show Disney smoking. Disney, however, still insisted that smoking was not appropriate for a family movie, so we only see the aftermath of Walt's smoking session, with Disney stubbing out a cigarette. Early references in this movie to Walt being a smoker is hearing his cough before meeting P.L. Travers. Tom Hanks has said that Robert B. Sherman told him that Walt used to smoke up to two packs a day, and you always knew when he was coming because you could hear his cough in the background of wherever he was. Disney died of lung cancer in 1966.
The emotional weight of the scene featuring the song "Feed the Birds" is based on the fact that it was Walt Disney's personal favorite song. According to Richard M. Sherman, Walt would drop by the Shermans' office and ask Richard to play the song when he felt depressed. It got to the point that he would drop by and simply say, "Play it", and they'd know what he wanted. According to Richard M. Sherman, Walt felt that the song was a perfect summation of why he created Walt Disney Pictures in the first place.
Leigh Anne Tuohy: The real-life subject behind director John Lee Hancock's previous movie, The Blind Side (2009), cameos as one of the guests inside Disneyland.