(CBSNews.com) - A 16-year-old boy scrambled over an airport fence, crossed a tarmac and climbed into a jetliner's wheel well, then flew for five freezing hours to Hawaii - a misadventure that forced authorities to take a hard look at the security system that protects the nation's airline fleet.
The boy, who lives in Santa Clara, Calif., hopped out of the wheel well of a Boeing 767 on the Maui airport tarmac Sunday. Authorities found the high school student wandering the airport grounds with no identification.
"He was weak. He hung from the wheel well and then he fell to the ground and regained some strength and stood up and started walking to the front of the aircraft," Maui airport manager Marvin Moniz told CBS News.
The teen was questioned by the FBI and taken by ambulance to a hospital, where he was found to be unharmed.
FBI spokesman Tom Simon in Honolulu said the teen did not remember the flight from San Jose.
"Kid's lucky to be alive," Simon said. "It's amazing that he survived that."
It was not immediately clear how the boy stayed alive in the unpressurized space, where temperatures at cruising altitude can fall well below zero and the air is too thin for humans to stay conscious. An FAA study of stowaways found that some survive by going into a hibernation-like state.
"It's so rare that one can survive at such an extreme environment for so long,'' said CBS News aviation consultant Capt. Chesley Sullenberger.
An FAA review of high-altitude wheel well survivors said they typically clamber past the main landing gear into a wing recess area next to where the gear retracts. On some aircraft, that space is large enough for two small adults.
The plane's own machinery can aid a stowaway's survival, at least initially. Warmth radiating from the wheels, which heat up on the runway during takeoff, and from hydraulic fluid lines can moderate the temperature. But those effects dissipate, and at cruising altitude the temperature in the wheel well would be about minus 30 degrees, estimated John Hansman, a professor of aeronautics and astronautics at the Massachusetts Institute of Technology.
The FAA found that all wheel-well stowaways will lose consciousness at high altitude from lack of oxygen, and that their freezing bodies go into a state somewhat similar to hibernation. At 38,000 feet - the cruising altitude of the Hawaiian Airlines flight - the outside air temperature is about minus 85 degrees. That would usually be deadly, but some people survive because their breathing, heart rate and brain activity slow down.
On Monday, authorities tried to determine how the boy slipped through multiple layers of security, including wide-ranging video surveillance, German shepherds and Segway-riding police officers.
Security footage from the San Jose airport verified that the boy climbed a fence and crossed a runway on Sunday morning to get to Hawaiian Airlines Flight 45, Simon said.
That airport, in the heart of Silicon Valley, is surrounded by fences, although many sections do not have barbed wire and could easily be scaled.
The boy climbed over during the night, "under the cover of darkness," San Jose airport spokeswoman Rosemary Barnes said Monday.
Hours later, surveillance video at Kahului Airport showed the boy getting out of the wheel well after landing, according to a statement from Hawaii's Department of Transportation. The video was not released because of the ongoing investigation.
Hawaiian Airlines spokeswoman Alison Croyle said airline personnel noticed the boy on the ramp after the flight arrived and immediately notified airport security.
"Our primary concern now is for the well-being of the boy, who is exceptionally lucky to have survived," Croyle said.
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."
A congressman who serves on the Homeland Security committee wondered how the teen could have sneaked onto the airfield unnoticed.
"I have long been concerned about security at our airport perimeters. #Stowaway teen demonstrates vulnerabilities that need to be addressed," tweeted Rep. Eric Swalwell, a Democrat who represents the San Francisco Bay Area's eastern cities and suburbs.
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 were 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.
His motives are also in question. Sources told CBS affiliate KGMB in Hawaii the boy may have been trying to reach Africa to visit relatives, but hopped on the first plane he saw and ended up in the middle of the Pacific.
San Jose police say they will forward the findings of their investigation to the district attorney, who can decide whether to file criminal charges in California.
The FAA says 105 stowaways have sneaked aboard 94 flights worldwide since 1947, and about 1 out of 4 survived. But agency studies say the actual numbers are probably higher, as some survivors may have escaped unnoticed, and bodies could fall into the ocean undetected.
In August, a 13- or 14-year-old boy in Nigeria survived a 35-minute trip in the wheel well of a domestic flight after stowing away. Authorities credited the flight's short duration and its altitude of about 25,000 feet. Others who hid in wheel wells have died, including a 16-year-old killed aboard a flight from Charlotte, N.C., to Boston in 2010 and a man who fell onto a suburban London street as a flight from Angola began its descent in 2012.