Only a handful of protesters stayed through the night, and flights resumed at the airport early in the morning. But by afternoon, several hundred demonstrators had returned, responding to a call for a new rally.
Protesters were wearing the signature black of the movement that began in opposition to a bill allowing extradition to mainland China but has morphed into a broader call for democratic freedoms, AFP reported.
They chanted "Stand with Hong Kong, stand for freedom," as passengers scrambling to catch rescheduled and delayed flights wheeled their luggage through the airport.
Authorities canceled all remaining flights into and out of the airport Monday afternoon after thousands of protesters flooded the building.
Operations resumed early Tuesday morning, but a massive backlog of canceled flights meant many take-offs were being delayed or canceled.