BOISE, Idaho (AP) — Forrest Bird, an inventor whose medical respirators breathed life back into millions of patients around the world, has died. He was 94.

His wife, Pamela Bird, said he died Sunday morning of natural causes at their northern Idaho home in Sagle, a base from which he traveled extensively around the world and was often recognized due to his 6-foot-4 height and unique, double-framed, flip-up glasses.

"People would say 'Thank you for saving my grandson. Thank you for saving my life," said Pamela Bird, also noting the many cards and letters that arrived in the mail with similar messages.

Forrest Bird is credited with creating the first low-cost, reliable medical respirators in the 1950s. In 1970 he created the "Babybird" respirator that significantly reduced infant mortality.

"I work as if I were going to be the next person to need a respirator," Forrest Bird told The Associated Press in a 1981 interview. "I share in the benefits I bestow on others and my work has enriched my life."

He never stopped inventing, and had patents pending at his death, his wife said. He was also a keen aviator, and at 92 was still doing spins and flips in his collection of aircraft, and also piloting his 12-passenger Bell helicopter.

"He's one of my heroes," said his step-daughter, Rachel Schwam, 31, who herself was saved by the Babybird after being born prematurely and now has two daughters of her own. "He never liked honors or recognition, but he deserves it."

He had advanced degrees in science and medicine, and his long list of honors include two that came from presidents. In 2008, he received the Presidential Citizens Medal from President George W. Bush, and in 2009 the National Medal of Technology and Innovation from President Barack Obama.

In photos with each president, Bird is wearing double-framed glasses with two sets of lenses, and he has one set flipped up. Pamela Bird said he started wearing the glasses in his 30s to avoid wasting time searching for glasses by having one pair for seeing both close up and far away.

She said he also one time bought 144 of the exact same style of shirt to avoid wasting time shopping. At night he filled a yellow pad with a list of items he planned to accomplish the next day.

Forrest Morton Bird was born June 9, 1921 in Stoughton, Mass., and graduated from high school at age 14, his family said, and was noted for repairing neighbors' tractors with car parts

With the encouragement of his father, a World War I pilot, Bird studied aviation. He made his first solo flight at 14, and was pursuing multiple pilot certificates by 16.

Bird enlisted in the Army Air Corps in 1941 and, with his advanced qualifications, entered as a technical training officer. He kept inventing, developing breathing devices for when aircraft started exceeding altitudes at which pilots could breathe unaided.

Respirators at the time were designed to allow healthy, young male pilots to fly at high altitudes. But Bird started experimenting so they could be used by someone younger, or older or unhealthy.

He ultimately produced the Bird Mark 7, which he called the Model T Ford of respirators because it was easy to maintain and repair.

"It's saved countless lives," said Rini Paiva, executive director of the National Inventors Hall of Fame, which inducted Bird in 1995. "He made a very big impression on other inductees. They looked at him as someone who was a legendary figure."

He formed a company but sold it in the late 1970s so he could escape the demands of production, and focus on invention. He retained development centers, including one in northern Idaho.

"We were just fortunate to have his influence in our state," said Jay Larsen of the Idaho Technology Council, which inducted Bird into its hall of fame in 2012. "He's a giant among innovators and inventors in Idaho."

Bird is survived by his wife, a daughter and two grandchildren.

The family planned a private service on Monday and a public service on Saturday at the Bird Aviation Museum & Invention Center in Sagle.