An aviation expert says a fatal plane crash in Masterton was most likely due to issues with ground control

Two pilots were killed when their planes collided in mid-air over Hood Aerodrome yesterday morning.

One had just dropped four skydivers into the air, and was returning to land.

The other was a training plane.

Former Aviation New Zealand CEO Irene King says airports have really good procedural controls to manage planes once they are in the air.

She says it's obvious there's been a significant failing in those controls.