Christchurch boy Ryan Hodgkinson, 14, flying with 77-year-old instructor Thomas Orr, landed short of the runway at Matamata Aerodome in Waharoa around 5pm.
Ryan suffered serious injuries and was airlifted to Waikato Hospital.
He was in a critical but stable condition, and his family was with him, a hospital spokeswoman said today.
His father, Ian Hodgkinson, would release a statement later today.
Mr Orr, from Taupo, suffered moderate back injuries and was also taken to hospital for treatment.
He was progressing well in a ward, Waikato Hospital communications director Mary Anne Gill said.
His wife, former Taupo mayor Joan Williamson-Orr, said the couple's thoughts were with Ryan.
Ryan, a student at Christchurch's Middleton Grange School, was taking part in an Air Training Corps camp.
Air Force media adviser Squadron Leader Kavae Tamariki said the camp was to give cadets experience with gliders. It was attended by cadets from throughout New Zealand.
Matamata police Sergeant Graham McGurk said a number of people witnessed the crash which happened about one kilometre away from the southern end of the airfield.
The Civil Aviation Authority is investigating how the accident occurred.
Commandant Guy Bendall, of the New Zealand Cadet Forces, said last night Ryan was one of 20 teens from around the country taking part in the camp.
The glider crashed minutes after takeoff but he did not know who was in control at the time of the accident, he told The Dominion Post.
