The Aviation Industry Association says the sector's governing body is acting in a draconian way by grounding a charter airline.
An investigation is under way after the Civil Aviation Authority said Air National's simulator training records might have been falsified.
On Wednesday, the High Court ruled that the suspension should be lifted, but gave the authority 24 hours to appeal, which it intends to do.
Air National operates the Christchurch-to-Hokitika route for Air New Zealand and says it has put other planes on the route.
The chief executive of the Aviation Industry Association, Irene King, says the allegations do not amount to a safety issue.
The authority says Air National was suspended on Friday after a routine audit showed training records might have been faked.