Masterton's community-owned Hood Aerodrome remains closed to the public during the Covid-19 lockdown, but open for essential flights.
Planes flying in and out of the council-run airport are not joyrides, but top dressing planes serving drought-hit Wairarapa.
As part of Covid-19 Alert Level 4, Hood is closed to all but essential services.
Emergency services will use the airstrip as needed.
Agriculture aircraft take off in the morning and come back at night, using farm strips for the actual fertiliser applications, aerodrome manager David Hayes said.
"The airfield is open to the Life Flight fixed-wing aircraft, but the only planes really flying are agricultural aircraft - and they've been busy.
"With the drought, and recently a bit of rain, farmers are keen to fertilise to get as much growth as possible before it gets too cold.
"They might look like recreational aircraft to the uninitiated, but these aircraft are essential services."
People should be avoiding the site unless they were involved in the essential flights, Mr Hayes said.
Four different groups of people were locked down in their separate accommodation at the airfield.
Although people were locked down at accommodation at the airfield, they were abiding by government guidance, Mr Hayes said.
"Some have accommodation in their hangars, and in case one of the operators has accommodation on site.
"I believe they are following the rules, but I did get a report of a member of the public walking their dogs on the airfield.
"That's basically trespassing, and potentially dangerous, given that aircraft are still operating out of Hood."
Plane operators do need to have a risk assessment and management plan for the Covid-19 coronavirus. The loader driver cannot go into the aircraft with the pilot, to maintain social distancing.
Mr Hayes said required maintenance to keep the Hood operationally safe was going on.
This includes runway inspections, mowing, and bird control.
"This is a great community asset, and that's shown by how much it is continuing to be used in a state of national emergency."
A $1 million package of upgrades to the airfield to bid for a return for commercial flights is part of Masterton District Council's annual plan.
Improvements under consideration include new hangars and runway widening.
The district council is still taking submissions on the plan, which also asks for public opinion on plans for Henley Lake, the Masterton Town Hall and civic centre, and the town's skate park.
Public consultation on the plan, and the district's speed review, is due to close on Monday 20 April.
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