Air Canada cannot use construction at Toronto's Pearson airport as an excuse for forcing a 15-year-old boy to spend a long, scary night alone, says the boy's mother.

Derrin Espinola was flying alone on May 1 from Denver to Thunder Bay, with a stopover in Toronto, when a flight delay leaving Denver caused the teen to miss his connecting flight.

Espinola said that when he arrived in Toronto around 8 p.m., Air Canada rebooked him on a flight to Thunder Bay the following day, at 6 p.m., but did not offer him any accommodation or vouchers for food.

"I was trapped in the airport and there was nowhere I could go. I could not leave. I could not get a hotel, because I am a minor," Espinola told CBC News in an interview a week after his long, lonely night. "It was like being held prisoner."

'I didn't really know what was going to happen to me,' said Derrin Espinola, 15, of his night spent alone at Toronto's Pearson airport. (Karin Patock)

An Air Canada spokesperson said in a written statement that the company was "truly sorry" to learn of Espinola's experience.

The statement pointed to the Greater Toronto Airports Authority's runway construction project as the cause of the delays, "which was exacerbated in this case by adverse weather." It said the airline's preparations included reserving hotel rooms and having "a service provider for chaperoning minors staying at hotel on standby."

"We had dedicated teams of customer service managers and agents actively combing passenger lines and at service desks to provide the appropriate arrangements and respond to customers' questions."

Air Canada's statement doesn't explain why Espinola was not looked after.

'Very tired, very scared'

The teen said he spent part of the night running between Air Canada service desks explaining that he was a minor and needed help. When none was offered, he did his best to stay alert and awake for fear he would be robbed if he let his guard down.

"I was very hungry, very tired, very scared," Espinola said. "I didn't know really what was going to happen to me."

Meanwhile, his mother, Karin Patock, said she spent 10 hours on the phone, trying to get through to Air Canada and make arrangements for her son.

Airline policy promises help

Patock said she purposely booked with Air Canada from Denver through to Thunder Bay, trusting the airline would live up to the policy about flight delays stated on its website: "Youths travelling alone (ages 12 to 17) … will be taken care of by our agents. We will also arrange for accommodations, meals and transportation if needed."

Air Canada knew that a three-hour flight delay in a departure would cause her son to miss his connecting flight, but did not make any contingency plans for him, Patock said.

Instead, she said, the airline "rebooked him like any other person, into the next day with no thought what's going to happen to him when he lands in Toronto in one of the biggest airports in Canada, all by himself."

Patock was making the three-hour drive from her home in Geraldton, Ont., to pick up her son in Thunder Bay when the events started to unfold.

'Unacceptable'

Phone calls to Air Canada got a message, "basically saying 'the airport is under construction and we cannot accommodate anyone right now, so call back later,'" she said. "To me that is unacceptable"

Air Canada must have known back in January when she booked her son's ticket that the construction at Pearson would cause delays, Patock said, and if they'd warned her, Espinola could have connected through Winnipeg instead.

In the end, the family intervened and booked the teen a flight, at their own cost, on another airline, Patock said.

It was to save him from spending another night alone in Toronto, after the May 2 flight he'd been booked on was cancelled and Espinola was rebooked, a second time, on an Air Canada flight departing May 3.

Patock has filed a complaint with Air Canada and the Canadian Transportation Agency in hopes of preventing any other teen from going through what her son did.

"It has been a challenge with the ongoing runway construction at Toronto Pearson, which was also compounded by severe weather conditions last week in the Toronto-Montreal-Ottawa and surrounding areas, including recent adverse conditions in Thunder Bay," a spokesperson for Air Canada wrote in an email in response to questions from CBC News.

The airline said it is looking into what happened with Espinola's flight and will be "reaching out to the family."