A student flying the second aircraft managed to land the damaged plane at the training school's airstrip.
It is likely the Cessnas collided as the uninjured student climbed higher into the air while Ms Neeson and Mrs Smallman were making their way back towards Feilding Aerodrome, an interim factual report into the tragedy by the Transport Accident Investigation Commission (TAIC) states.
"Impact marks on the leading edge of the right wing (of aircraft ZK-TOD) were consistent with having been struck by a tyre, with black rubber deposit on the surface of the indentation," the report said.
"Outer sections of the right wing, including the aileron, were found about 280 metres north of the main wreckage."
The engine of the second plane, ZK-JGB, stopped soon after the midair collision and the student managed to glide back to the aerodrome and land on the side of the runway.
He later told investigators he "heard a loud noise and the aircraft nose then pulled down".
"The fixed non-retractable nose wheel of ZK-JGB had been forced rearward. The fuel line to the carburettor was broken, as well as the carburettor. This is considered the most likely reason for the engine stopping in flight," the report said.
The commission said it had a number of lines of inquiry still to investigate, including the standard of pilot training in New Zealand and whether the growing level of pilot training in the country had an effect on the level of air traffic services at uncontrolled aerodromes, such as Feilding.
The inquiry was yet to establish if any malfunction in either aircraft could have contributed to the collision, it said.
Ms Neeson grew up near Tokirima, south of Taumarunui, and boarded at Sacred Heart Girls' College in Hamilton.
