Dorothy Hoffner, a 104-year-old Chicago woman whose recent skydive could see her certified by Guinness World Records as the oldest person to ever jump from a plane, has died.

Hoffner's close friend, Joe Conant, said she was found dead Monday morning by staff at the Brookdale Lake View senior living community. Conant said Hoffner apparently died in her sleep on Sunday night.

Conant, who is a nurse, said he met Hoffner -- whom he called Grandma at her request -- several years ago while he was working as a caregiver for another resident at the senior living center. He said she had amazing energy and remained mentally sharp.

"She was indefatigable. She just kept going," he said Tuesday. "She was not someone who would take naps in the afternoon, or not show up for any function, dinner or anything else. She was always there, fully present. She kept going, always."

On Oct. 1, Hoffner made a tandem skydive that could land her in the record books as the world's oldest skydiver. She jumped out of a plane from 13,500 feet (4,100 metres) at Skydive Chicago in Ottawa, Illinois, 85 miles (140 kilometres) southwest of Chicago.

"Age is just a number," Hoffner told a cheering crowd moments after landing. It was not her first time jumping from a plane -- that happened when she was a spry 100 years of age.

Conant said he was working through paperwork to ensure that Guinness World Records certifies Hoffner posthumously as the world's oldest skydiver, but he expects that will take some time. The current record was set in May 2022 by 103-year-old Linnea Ingegärd Larsson of Sweden.

Conant said Hoffner didn't skydive to break a record. He said she had so thoroughly enjoyed her first jump that she just wanted to do it again.

"She had no intention of breaking the record. And she had no interest in any publicity or anything. She wasn't doing it for any other reason than she wanted to go skydiving," he said.

Skydive Chicago and the United States Parachute Association celebrated Hoffner in a joint statement Tuesday.

"We are deeply saddened by Dorothy's passing and feel honored to have been a part of making her world-record skydive a reality.

"Skydiving is an activity that many of us safely tuck away in our bucket lists. But Dorothy reminds us that it's never too late to take the thrill of a lifetime. We are forever grateful that skydiving was a part of her exciting, well-lived life," they said.

Conant said Hoffner worked for more than four decades as a telephone operator with Illinois Bell, which later became AT&T, and retired 43 years ago. The lifelong Chicago resident never married, and Conant said she had no immediate family members.

A memorial service for Hoffner will be held in early November.

"She was a dear friend who was an inspiration," Conant said.