Like a big-wave surfer anticipating the next winter swell, retired Aloha Airlines pilot David Bigelow was giddy on the morning of his final flight as it became apparent the conditions were ideal for a record-breaking attempt to reach an altitude of 40,000 feet in his single-seat DG-400 sailplane.

Bigelow, 69, had spent months meticulously preparing for the unpowered flight that would lift off Friday morning from the Waimea-Kohala Airport, according to son Dan Bigelow, 44, who lives in Ha'iku, Maui.

"He knew that would be the day," his son said.

The elder Bigelow had nearly 50 years of pilot training and experience to call on and left nothing to chance. In the six weeks leading up to Friday's attempt, he had flown a total of 92 hours in his sailplane, and in the preceding months had pored over weather and air current charts on his computer.

After setting a new state altitude record for gliders of 33,531 feet in April, Bigelow went even higher, to 33,600 feet, a couple months ago — about 4,500 feet higher than the summit of Mount Everest.

"Everybody should realize this was an intentional and scientific undertaking. He understood the dangers," Dan Bigelow said.

Family members and friends believe Bigelow caught the "big wave" on his final ascent and was carried to record-breaking altitudes before his sailplane mysteriously spiraled back to Earth and broke apart in midair, leaving a 7- to 10-mile path of debris across a barren lava flow at the 9,800-foot elevation of Mauna Loa.

The pilot's remains were recovered Sunday by National Park Service rangers.

Dan Bigelow and others speculate his father likely suffered a problem with his oxygen supply and fell unconscious, a comforting scenario for his family.

"If he did black out, I can't think of a better way," Bigelow said. "It's like he got to 40,000 feet and God said, 'You're close enough so I'll take you from here.' "

David Bigelow was an Air Force fighter pilot during the Vietnam War who joined Continental/Air Micronesia in 1968. He began flying for Aloha Airlines in 1984 and, while living in Windward O'ahu, took up hang-gliding from the cliffs above Makapu'u. Bigelow also designed and built his own flex-wing hang gliders and ultralight aircraft and became enamored with sail- planes, flying out of Dillingham Airfield in Mokul''ia.

After a career spent in the cockpit of big, loud jets, Bigelow savored the solitude and quiet of piloting the sleek, engineless gliders, according to his son.

"It's more of an artful type of flying. Once you're released you have to find your lift," Dan Bigelow said. "The only sound you hear is the wind through the wings. There's no fuel, no engine, no noise. He loved it."

Bigelow retired in 1990, moving to Waimea, where he built a home with his wife, Patty.

As a longtime pilot, Bigelow was expert at interpreting shearlines and other weather formations, and was familiar with the air currents, or "waves," that flow up and around large mountains, his son said. He also knew that some of the world's biggest "waves" are generated around the volcanoes on the Big Island.

On Friday morning, while the rest of the state was bracing for a potentially destructive wind storm, Bigelow was towed into the air for what was expected to be a five- to six-hour flight. Several glider pilots who had gone up ahead of him radioed Bigelow with information on the conditions.

He spoke with Patty twice during the flight, the last time at 11:30 a.m. to tell her he was at 18,000 feet over Hualalai volcano, where he planned to catch "the wave" to the taller Mauna Kea.

"He went up, up, up in the elevator. He was looking for the big wave," Dan Bigelow said.

At 1 p.m., Bigelow radioed his Mauna Kea Soaring Club buddies on the ground that he was at 28,000 feet and headed toward Mauna Loa, whose updrafts would carry him even higher. He reported he was riding the wave at 1,000 feet per minute, "an incredible rate" of ascent, according to his son.

At some point, Bigelow put on an oxygen mask that prevented him from speaking on his radio, but he continued to communicate through a series of microphone clicks.

Then the clicks stopped.

Authorities were notified at 6:20 p.m. that Bigelow was missing.

Dan Bigelow said they are hoping to find the sailplane's flight recorder to verify its ultimate altitude.

"He got out of the party at the high point. He was at the top of his game," his son said. "He did it with style and caught the big wave to where he wanted to go."

In addition to his love of flying, David Bigelow was a "computer geek" and avid surfer, kayaker, diver and sailor, according to his son.

A service is planned for 2 p.m. Jan. 31 at the Waiki'i Community Clubhouse in Waimea.

The crash is being investigated by national park rangers and the National Transportation Safety Board.

The last fatal sailplane accident in Hawai'i occurred on April 6, 2005, when a for-hire sightseeing flight crashed near Dillingham Airfield, killing the pilot and injuring two passengers.