Tonga's chief justice, Robin Webster has granted an injunction sought by Fly Niu Airlines after the Civil Aviation Department cancelled its operators certificate.
Earlier this month, the government announced only one airline could operate domestically.
The routes were granted to Peau Vava'u, which has also been known as Air Waves of Vava'u, and is partly owned by the Crown Prince Tupouto'a
Both airlines had been providing domestic services since June when Royal Tongan Airlines collapsed.
The Civil Aviation Department had said it received only one application.
Atu Finau of Fly Niu says that's correct.
"No we didn't apply. We're questioning the validity of the policy, that's basically it."
The head of Fly Niu, Atu Finau.
A hearing between Fly Niu Airlines, the government and the Civil Aviation Department has been set for the 6th of September.
Meanwhile Fly Niu was back in the skys yesterday afternoon running flights to Ha'apai and Vava'u.
