Colorado authorities launched an extensive hunt Thursday for a 6-year-old boy they feared had been carried away in a flying homemade balloon -- only to find the boy back at home in the attic over the garage.

The case mystified authorities for several hours Thursday, first in chasing the flying-saucer-shaped balloon across two counties before it crashed gently in a dirt field. Then, after the balloon turned up empty, authorities shifted to a ground search for the boy, fearing he may have fallen out in flight.

The harrowing scene played out live on TV, until police announced that the boy had been hiding in a cardboard box at home the whole time.

"It was a miracle to see him," his mother, Mayumi Heene, told reporters Thursday evening while grasping her three boys, including the 6-year-old, Falcon.

"My legs were weak," Falcon's father, Richard, said about seeing his son safely on the ground and at home. "I couldn't even walk from one room to the next."

Richard Heene, an amateur storm chaser, said the family was tinkering with the balloon when he scolded Falcon for getting inside a compartment on the craft.

"We were working on an experimental craft," he told reporters. "I call it the 3D LAV, a low-altitude vehicle for people to pull out of their garage and hover above traffic for about 50 to 100 feet. It's still in the very early stages of the invention."

He said Falcon's brother had seen the boy inside the compartment before it took off, and that's why they thought he was in there when it launched.

"I yelled at him. I'm really sorry I yelled at him," Heene said as he hugged his son during a news conference.

This isn't the first time family has faced the national spotlight. It has been featured twice on the ABC series "Wife Swap," first on Oct. 3, 2008, and again when the family was voted back for the 100th episode of the show, which aired on March 13, 2009.

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RELATED: Falcoln Heene on 'Wife Swap,' Youtube Music Videos

SLIDESHOW: Stills from the Heene brothers' Youtube video.

And Richard Heene has participated in videos as part of a team that calls itself the "psyience detectives."

Based out of Fort Collins, Colo., Heene collects information to prove that rotating storms create their own magnetic fields, the Denver Post reported. In 2002, Heene started with lab experiments and then moved to dust devils, according to the Post, and three years later, Heene flew a plane around Hurricane Wilma's perimeter.

In a 2007 interview with the Post, Heene described becoming a storm chaser after a tornado ripped off a roof where he was working as a contractor.

Pursuing bad weather was a family activity with the children coming along as the father sought evidence to prove his theory that rotating storms create their own magnetic fields.

Although Heene said he had no specialized training, the family had a computer tracking system in its car and a special motorcycle.

But on Thursday, the family simply seemed relieved to find their son alive.

Mayumi Heene reportedly was sitting on the couch when her son walked in to see her. Authorities never looked in the attic where the boy was hiding from his father.

"I was in the attic and he scared me because he yelled at me," Falcon said. "That's why I went in the attic."

While the balloon was still airborne and the boy still feared inside, authorities scrambled for a way to rescue him. The Colorado Army National Guard sent an OH-58 Kiowa helicopter and was preparing to send a Black Hawk UH-60, possibly to lower someone to the balloon. The Guard also was working with pilots of ultralight aircraft on the possibility of putting weights on the homemade craft to weigh it down.

But after about two hours in the air, the balloon eventually landed gently on its own in a dirt field. Sheriff's deputies secured it by tossing shovelfuls of dirt on one edge while they investigated, determining the craft was empty.

The balloon reached an elevation of 8,500 feet and speeds of possibly as fast as 60 mph, Fox 31 in Colorado reported. It wasn't going "frighteningly fast," Fox 31 reporter Kim Psey said.

Federal Aviation Administration spokeswoman Laura Brown said the agency tracked the balloon through reports from pilots and notified air traffic control facilities in the region. Some commercial flights out of Denver were affected.

The Web site ABC used to promote "Wife Swap" portrays the family members as thrill-seekers.

"When the Heene family aren't chasing storms, they devote their time to scientific experiments that include looking for extraterrestrials and building a research-gathering flying saucer to send into the eye of the storm," the Web site said.

The Heenes were criticized for their chaotic parenting style when Karen Martel of Connecticut entered the household as the new "wife." Martel's husband runs a child-proofing business, and she knew a thing or two about safety.

According to a recap on TVRage.com, the 100th episode finds two families swapping with each other who are returning by a viewers vote.

"One mom believes she is psychic and can speak with the dead, plus has control over the weather. The other is a family of storm chasing science-enthusiasts. The kids in the families will face off in a table meeting"

The runaway balloon made for quite a sight Thursday.

"We were sitting eating, out looking where they normally shoot off hot air balloons. My husband said he saw something. It went over our rooftop. Then we saw the big round balloonish thing, it was spinning," said neighbor Lisa Eklund.

Click here for more on this story from MyFOXColorado.com.

Click here to read more on on this story from the Devner Post.

Foxnews.com's Michelle Maskaly and The Associated Press contributed to this report.