Thousands of demonstrators in black are sitting in the airport, while hundreds more are walking over to join the protest.

Earlier today, there were baggage carts and barriers blocking access to the check-in area -- but protesters broke through and are now in both the arrivals and departures hall.

180 flights from Hong Kong to Boston, Taipei, and more are canceled

Around 180 flights leaving Hong Kong International Airport from now until the early hours of Tuesday morning have been canceled, according to the airport’s website. The first scheduled departure now shown is a Hong Kong Airlines flight to Haikou, China, at 7 a.m. tomorrow.

Travelers have been caught in the mix -- but protesters are trying to help them out. This afternoon, they cleared the way and opened a path in the crowd every time a passenger needed to get through to the check-in counters.

Still, the sheer number of protesters has thrown the airport into chaos. Even if protesters can get through the crowds, check-in services are now shut down and all departing flights have been canceled.

Hong Kong's airport is one of the busiest in the world, handling 1,100 passenger and cargo flights daily, with services between the city and about 200 international destinations.