Update at 6:05 p.m. ET: In the middle of a news conference, authorities have just announced that Falcon Heene has been found at home and is fine.

Update at 6:09 p.m. ET: Falcon was hiding in a cardboard box in the garage attic, police say. The house had been searched twice before.

Watch live coverage from KUSA.

Update at 6:17 p.m. ET: The authorities theorize the boy hid after the balloon broke loose, afraid that his parents would be angry.

Update at 5:47 p.m. ET: Authorities are trying to determine whether the circled black object is the box that was originally attached to the balloon. Falcon Heene was seen climbing inside it before the balloon broke free. Authorities still do not know whether he was in the box as his father's homemade helium balloon sailed away. Photo by Denver Post from KUSA-TV footage.

Previous updates:

Update at 3:35 p.m. ET: The balloon has slowly spun to a crash-landing in a field, surrounded by rescuers. No word on boy's condition.

Update at 3:51 p.m.ET: Officials say there is no sign of the boy.

Update at 3:57 p.m. ET: The boy has been identified as Falcon Heene (left), the 6-year-old son of Richard and Mayumi Heene of Fort Collins. His family is known as storm chasers and were featured last October on the show Wife Swap, the Fort Collins Coloradoan writes. Here are the episodes.

Larimer County Sheriff's spokeswoman Kathy Messick said the aircraft was kept in the backyard and is "a family project that was never meant to be flown by anybody."

Messick said the device has a box with a small battery compartment. Sheriff's officials and family members had believed the child was located in the compartment, but he was not aboard when the aircraft landed about 1:40 p.m. MT near the town of Hudson.

"The family is very upset right now," Messick said.

Update at 4:05 p.m. ET: On his MySpace page, Richard Heene writes that he hosts "a documentary series and radio show to investigate the mysteries of science, The Science Detectives, and I chase storms. Last year I flew into Hurricane Wilma to take magnetic field measurements. This year I rode a motorcycle into a mesocyclone."

Heene lists his age as 48 and his status as "single." He describes himself as a "Psyience Detective."

People he'd like to meet: "Real Aliens from outer space and conduct a full interview with them. Are there really aliens, like Greys, and Blues?"

Update at 4:53 p.m. ET: A sheriff's official says that the boy climbed into a box attached to balloon but that the basket was not found where the craft landed. A search is continuing.

Update at 4:57 p.m. ET: Officials now say they believe the boy might not have ascended with the balloon and is hiding near his home.

"At this point, we are thinking that he did not fall out of the balloon and is somewhere on the ground," said Larimer County Sheriff's Office spokeswoman Eloise Campanella. "The basket itself was not breached. It does not look like he fell out of it, but again, this is all conjecture."

"I'm very confident we will find him. I think it's a matter of him being a little scared," she said. "Maybe he's not ready to be found."

Update at 5:14 p.m. ET: The Denver Post writes that in a 2007 interview, Richard Heene described becoming a storm chaser after a tornado ripped off a roof where he was working as a contractor, and said that in 2005 he had flown a plane around the perimeter of Hurricane Wilma.

"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," the Post writes. "Although Richard said he has no specialized training, they had a computer tracking system in their car and a special motorcycle."

Original posts:

Officials north of Denver are scrambling to try to figure out how to rescue a 6-year-old boy who has climbed into a hot-air balloon aircraft and is floating away, the Associated Press reports.

Update at 2:40 p.m. ET: Larimer County sheriff’s spokeswoman Eloise Campanella says the device, shaped like a flying saucer, could rise as high as 10,000 feet.

The balloon was last seen south of Milliken, which is about 40 miles north of Denver, the AP says.

FAA has been notified by it is unclear whether traffic controllers have picked it up on radar, the AP says.

Update at 2:42 p.m. ET: KUSA TV says the craft is an experimental aircraft that has a large helium balloon attached at their home  in Fort Collins. 

Click here to link to KUSA's live webcast of the unfolding incident.

Update at 2:52: p.m. ET: The Fort Collins Coloradoan reports that family and officials say the boy got onto the aircraft and detached the rope holding it in place.

Update at 2:58 p.m. ET: USA TODAY's Doyle Rice says current winds around Fort Collins are out of the northwest at 14 mph, gusting to 20 mph, according to the National Weather Service.

Update at 3:16 p.m. ET: A Weld County sheriff's spokesman said a sibling saw the boy climb into the basket before the balloon took off. The door on the balloon was unlocked, so it's possible the boy had fallen out, she said.

Erik Nilsson, Larimer County Emergency Manager, told CNN affiliate KMGH, "The structure at the bottom of the balloon that the boy is in is made of extremely thin plywood and won't withstand any kind of a crash at all."

Update at 3:23 p.m. ET: The Colorado National Guard is sending an OH-58 Kiowa helicopter to try to rescue the boy, the Associated Press says.

(Screen grab from KUSA-TV shows the balloon at the moment it landed. Photo of Falcon Heene from ABC via AP. Richard Heene from his MySpace page. Family portrait shows Mayumi and Richard Heene at home in October 2008. Falcon is on his father's shoulders. The other boys are Ryo, 8, left, and Bradford, 10. Photo by Michael G. Seamans, The Coloradoan. Photos of balloon aloft by KMGH-TV via AP. )