The other pilots scrambled to uplift the occupants of the crashed aircraft and took them to the hangar to be checked over by ambulance staff, a police spokeswoman said.
A St John spokeswoman said one person had been seriously injured, while another was moderately injured.
They sent two ambulances and one helicopter to the scene, she said.
A man in his 20s was flown to Hawke's Bay Hospital and remains in a stable condition, according to a District Health Board spokeswoman.
The other was taken to Taupō Hospital by road, the St John spokeswoman said.
A Civil Aviation Authority spokesman said they had been notified of the incident and were gathering more information before a decision was made whether to launch an investigation.