How Did Teen Survive Flight Inside Plane's Wheel Well? At 38,000 feet, temperatures can drop to minus-85 degrees Fahrenheit.

April 22, 2014 -- It’s still unclear how a 15-year-old teenager stowed away inside the wheel well of a Hawaiian Airlines 767 and survived amid the high altitude, frigid temperatures and low oxygen as the plane flew for more than five hours.

Residents believe the teen lives in Santa Clara, Calif., with his parents and three siblings. His father is a cab driver, and neighbors say they only see the family in passing.

“They’re really quiet neighbors,” a neighbor said. “So we don’t hear noises or anything.”

READ MORE: Experts Question Plane Stowaway's Story

The boy made his way to a fence surrounding the San Jose Airport Saturday. He scaled it, evading several layers of security, including video surveillance, German shepherds and Segway-riding officers, airport spokeswoman Rosemary Barnes said.

“It does appear that he did scale a part of our perimeter fence line under the cover of darkness and remained undetected as he proceeded onto the aircraft ramp and then proceeded into the wheel well of the aircraft,” Barnes said.

As daylight broke, the boy remained undiscovered for the 8 a.m. takeoff. He chose the first plane he saw and may not have realized he would be in the air for more than five hours, FBI spokesman Tom Simon said.

"He got very lucky that he got to go to Maui but he was not targeting Maui as a destination," Simon said.

The boy is also lucky to be alive, given that wheel-well stowaways rarely surviving flight conditions. At 38,000 feet, the percentage of oxygen is a fraction of that at sea level, and the temperature ranges from minus-50 to minus-85 degrees.

What We Know About the Teen Stowaway Who Landed in Hawaii

An FAA study of stowaways found that some survive by going into a hibernation-like state.

The plane landed in Hawaii. About an hour later, at 10:20 a.m. Hawaii time, crews were startled by the teen coming out of the wheel well, Maui Airports District Manager Marvin Moniz said.

“He was weak. He hung from the wheel valve and then he fell to the ground and regained some strength,” Moniz said.

Many questions remain after the boy’s journey, including how no one spotted the teen until after the plane landed in Hawaii. Isaac Yeffet, a former head of security for the Israeli airline El Al who now runs his own firm, Yeffet Security Consultants, said the breach shows that U.S. airport security still has weaknesses, despite billions of dollars invested.

"Shame on us for doing such a terrible job," he said. "Perimeters are not well protected. We see it again and again."

Unlike checkpoint security inside the airport, which is overseen by the Transportation Security Administration, airport perimeters are policed by local authorities, as well as federal law enforcement.

Airport police are working with the FBI and the TSA to review security.

The boy was released to child-protective services in Hawaii and not charged with a crime, Simon said.

The city of San Jose, which owns and operates the airport, has no plan plans to pursue criminal charges against the teen based on the information available.

The Associated Press contributed to this report.