Emergency services were called to New Plymouth Airport on Wednesday night after haze was detected in the cabin of an Air New Zealand flight.
The pilot on board the Air NZ Bombardier Dash 8 Q300 flight to Auckland requested to return to New Plymouth and was met by fire trucks when it landed shortly after 8.30pm.
Air NZ said it was not an emergency landing.
The Fire Service Central Region shift manager told Newshub three fire trucks, a command unit and an incident support vehicle put on standby at the airport as a precaution.
Emergency services were stood down shortly after and engineers are carrying out a full check of the aircraft today.