The father of a teenager who miraculously survived a five-hour flight from California to Hawaii tucked in a jet's wheel well has said his son missed Africa, where he used to live, and was struggling at school.

Abdilahi Yusuf Abdi, of Santa Clara, California, said his 15-year-old son was always talking about going back to Africa, where his grandparents live. He came to the US four years ago.

The boy climbed into the wheel well before the Hawaiian Airlines Boeing 767 took off from San Jose for Maui on Sunday morning. Security video shows the boy jumping out of the plane after landing.

Mr Abdi told Voice of America that Honolulu police notified him of his son's journey. The teenager remains in hospital in Honolulu.

Airport chiefs said the boy was disoriented, thirsty and could barely walk after the freezing, low-pressure ordeal.

Security video of his arrival shows him dangling his feet for about 15 seconds from the wheel well before jumping about 10ft to the ground, landing on his feet and immediately collapsing, Maui district airport manager Marvin Moniz said.

Staggering toward the front of the plane, the soft-spoken boy, in a San Francisco Giants hoodie, asked a ramp agent for a drink of water, setting in motion national and local law enforcement investigations, calls for better airport security and a flurry of speculation about how anyone could survive such a perilous trip.

Taxi driver Mr Abdi said he learned of the perilous journey on Sunday when he received a call from police in Hawaii, but could not understand how he got to Maui and asked them to contact the San Jose Police Department.

"When I watched the analysis about the extraordinary and dangerous trip of my son on local TVs and that Allah had saved him, I thanked God and I was very happy," he said.

After the boy was discovered in Maui, FBI and Transportation Security Administration investigators questioned him and fed him teriyaki meatballs and rice from an airport restaurant and a box of macadamia nut cookies. The teenager, whose name has not been released, said he had been in an argument at home, went to the airport, and got on to the first plane he came to.

"He didn't realise he was in Maui - not at all," Mr Moniz said.

The boy told officials he evaded what was supposed to be a multi-layered airport security system in San Jose by climbing a fence.

That does not surprise airport security experts, who say that for all the tens of billions of dollars America has spent screening passengers and their bags, few airports made a comparable investment to secure the planes parked on the tarmac.

"No system is foolproof," said San Jose International Airport aviation director Kim Aguirre. "Certainly as we learn more, if we see any gaping holes, we will work to fill them."

She said a perimeter search found no holes or crawl spaces in the barbed-wire fence surrounding the 1,050-acre airport.

Santa Clara High School principal Gregory Shelby sent a note to staff saying the teenager, who has been in the US for about four years, speaks English as his second language and transferred into the district five weeks earlier.

Aviation security experts say San Jose is hardly alone when it comes to weaknesses in securing its airfield.

"What happened in San Jose can happen as we speak at other airports, because nobody can watch all these monitors" that feed video from around the airport, said Rafi Ron, former head of security at Tel Aviv, Israel airport. He now runs a security consulting firm.

That the teen survived is remarkable. At a cruising altitude of 38,000 feet, temperatures would have been well below zero and the air so starved of oxygen that he probably passed out. In response, his body could have entered a hibernation-like state, experts say.

The TSA said it has spent 80 billion dollars (£48bn) on aviation security since its inception shortly after the 9/11 attacks. That does not include perimeter security.

"We were investing all our resources in the front door, which were the passengers and their bags," Mr Ron said. "And we left the back door open."