The three Gupta brothers, accused by the public anti-graft watchdog of using their friendship with Zuma to influence policy and amass wealth, have denied any wrongdoing, as has Zuma. Ajay Gupta was declared "a fugitive from justice" by South Africa's chief prosecutor earlier this week.
South African police launched a search for Ajay Gupta on Thursday after he failed to report to law enforcement officials investigating alleged high-level influence-peddling in Zuma's government involving the Gupta brothers.
Leigh Gunkel-Keuler, a spokeswoman for Johannesburg's main airport, said Ajay Gupta was on an Emirates flight bound for Dubai on Feb. 6 at 8.30 p.m. local time (1830 GMT).
"I cannot confirm if Mr Ajay Gupta is back in the country; he may well be back in the country through another port of entry," Gunkel-Keuler said.
She added that the airport was handing over all relevant information to the Hawks, an elite police unit officially known as the Directorate for Priority Crime Investigation, which targets organised crime, economic crime and corruption.
Zuma resigned on Wednesday on the demand of the ruling ANC and was replaced on Thursday by Cyril Ramaphosa.
Among the eight were Gupta nephew Varun Gupta, who was an executive director of the Guptas' Shiva Uranium firm. Zuma's son Duduzane was a fellow director of Shiva.
Earlier this week the Hawks raided Gupta properties in Johannesburg in connection with the dairy farm, which prosecutors last month called a "scheme designed to defraud and steal".
Ramaphosa is expected to give more details about how he plans to tackle corruption and boost economic growth on Friday when he delivers his first state of the nation address.
(Except for the headline, this story has not been edited by NDTV staff and is published from a syndicated feed.)