The boy, locally named Charlie Joyce, died following the collision in the Dunclug area on Thursday afternoon.
Another 13-year-old boy involved in the crash was said to have been fighting for his life last night.
People who were in the area at the time rushed to try to help the two children before help arrived.
The air ambulance was among three emergency teams that responded.
The two boys were taken from the scene to the Royal Victoria Hospital in Belfast – one in the helicopter and the other in a roadside ambulance.
Sadly, Charlie Joyce died from his injuries.
The PSNI said a full investigation had begun and asked anyone who witnessed the crash, or had cellphone footage, to come forward.
Father Patrick Delargy, pastor of All Saints’ Church in Ballymena, visited the Joyce family on Friday.
The cleric said the boys’ parents were in shock after the tragic death of their baby boy.
“They were totally exhausted, they were coming back from hospital,” he told BBC NI.
“They are having a really hard time processing the whole thing.
“There are no words, I have a hard time finding the right words to say in these situations.”
Father Delargy said he prayed with the family and thought it brought them some comfort.
The priest also expressed hope that the injured boy would recover.
Other children from the Dunclug area had gathered around a makeshift memorial yesterday, where the words ‘RIP Charlie Joyce’ were written and bouquets of flowers laid.
Father Delargy expressed his support for the idea of a permanent memorial at the spot where the accident happened.
Father Delargy said: “It would be a good idea to have something there to remember the boy, and please God the other little boy is getting well.
“That would help people a lot.”
In a statement, the Northern Ireland Ambulance Service said it responded to a 999 call at 4.47pm on Thursday.
“NIAS dispatched three emergency crews and a medic to the scene and also tasked the Charity Air Ambulance, with the Helicopter Emergency Medical Service (HEMS) team on board, with the incident,” the statement read.
“Following initial assessment and treatment, one child was airlifted to the Royal Group of Hospitals, Belfast while the other was flown to the same location by ambulance.”
Ian Paisley, DUP MP for North Antrim, said the families involved were in his prayers.
Sinn Fein MP Philip McGuigan expressed his condolences.
“The local community was shocked and saddened by this tragic death. This is particularly devastating given the young boy’s age,” Mr McGuigan said.
“My thoughts and sympathies go out to his family, young friends and loved ones.”
Alliance MP Patricia O’Lynn described the incident as a “tragedy”.
“The entire North Antrim Alliance team sends their thoughts and condolences to the family at this difficult time,” she said.
On Friday, tributes poured in on social media for the deceased little boy.
A family friend wrote, “Heaven has won a very special angel with a beautiful smile and a beautiful nature.
“Charlie Joyce, in the arms of the angels now.”
She added, “God help his whole heartbroken family, rest in peace beautiful boy.”
Local boxing club, All Saints ABC, wrote: “This morning we woke up to the tragic loss of one of our young All Saints guns. Our thoughts and prayers are with the Joyce family.
The Doury Road Development Group, meanwhile, said it had decided to cancel a ‘Fairy GoodWood children’s workshop’ scheduled for today as a ‘show of respect for family and friends of young Charlie Joyce”.