Fisher, 60, was rushed to a hospital after getting off the flight at Los Angeles International Airport shortly after noon, according to the newspaper, citing emergency officials.
She was “in a lot of distress on the flight,” a source who was not authorized to talk about the incident told the Times.
Airport police responded to a report of a female passenger under cardiac arrest in Terminal 7, where they found Los Angeles Fire Department personnel performing CPR on the woman, according to Officer Alicia Hernandez.
Erik Scott, an LAFD spokesman, confirmed to KTLA that paramedics went to Gate 74 at LAX for a patient on inbound flight at 12:11 p.m., but he also did not provide the person’s name.
The patient was provided advanced life support and aggressively treated at the scene before being transported to an area hospital, he said.
Anna Akana, an actress and producer known for her YouTube channel, said she was on the United Airlines flight sitting near Carrie Fisher, and tweeted about the medical emergency that happened on board the plane.
According to Akana, Fisher “wasn’t breathing for 10 minutes or so.” The United crew, as well as doctors and nurses who happened to be on the flight, sprang into action immediately, administering CPR to the actress until the flight landed, according to tweets.
Following initial reports of Fisher’s illness, actor William Shatner tweeted, “I ask everyone to stop for a moment and send special thoughts to @carrieffisher.”
Mark Hamill, Fisher’s “Star Wars” co-star, also tweeted about the actress.
“As if 2016 couldn’t get any worse… sending all our love to @carrieffisher,” he wrote.
Fisher, also a published author, has been recently promoting her memoir, the “Princess Diarist,” which was based on diaries she wrote around the time of filming “Star Wars Episode IV: A New Hope.”
She will once again reprise the iconic Princess Leia role in “Star Wars Episode VIII.” The film is currently in post-production and is expected to come out at the end of 2017.
Fisher is the daughter of Hollywood actors Eddie Fisher and Debbie Reynolds.