Hong Kong airport faces disruption as pro-democracy protesters blocked access roads.
Trains to the airport were also halted with passengers forced to walk to the terminal.
Most flights were operating as normal, but delays were reported.
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Thousands of black-clad protesters tried to enter the terminal building but were stopped by riot police.
The airport was targeted after police and protesters clashed during a banned rally on Saturday.
Live warning shots were fired into the air and tear gas and water cannon used to disperse tens of thousands of protesters.
Images later showed riot police hitting people with batons and using pepper spray on a train in Hong Kong’s metro, the BBC reported.
Airport Authority Hong Kong said it was “aware that there have been calls for public activities in different parts of Hong Kong on 2 and 3 September”.
It added: “Passengers are advised to allow sufficient time to travel to the airport.
“Passengers may also check with their respective airlines, or visit the airport’s website and mobile app for updated flight information.”
Hong Kong-based Cathay Pacific said: “While certain public transportation services to Hong Kong international airport have resumed, some delays are still expected.
“We suggest passengers allow enough time for additional travel prior to their flight’s scheduled departure.
“While disruption events like these can change significantly and at short notice, rest assured we are doing everything we can in advance to minimise the impact to customers.”
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