Flights to and from Hong Kong's international airport were cancelled or delayed for a second day Tuesday as protesters continued to occupy the main terminal. And while many of the demonstrators left Tuesday night, following a clash with police armed with pepper spray and batons, they vowed to return to the airport Wednesday.

Hong Kong's Airport Authority said operations were "seriously disrupted" as it halted check-ins. More than 300 flights were affected Monday and Tuesday. The airport reopened on Wednesday, while the airport authority said it had obtained "an interim injunction to restrain persons from unlawfully and willfully obstructing or interfering" with airport operations.

Here's what Canadian travellers should know:

Is it safe to travel to Hong Kong?

The Canadian government advises travellers to "exercise a high degree of caution" if they are travelling to Hong Kong. It says Canadians should monitor local media while there, and avoid areas where demonstrations and large gatherings are taking place.

It also urges all Canadians travelling abroad to register in case of an emergency where they are visiting or back at home. The service also allows Canadians to receive important information in the event of civil unrest.

What are the protests about?

The recent wave of protests began June 9 as tens of thousands of people took to the streets of Hong Kong to protest a bill that would have allowed people suspected of crimes in the former British colony to be extradited to mainland China to face trial. China has a 99.9 per cent conviction rate, and there was concern people from Hong Kong would not get a fair trial. The bill was eventually suspended, but people want the bill fully withdrawn — something Chief Executive Carrie Lam has refused to do.

The protest movement has grown to a wider call for democracy, with people worried about the erosion of the "one country, two systems" that established certain autonomies for Hong Kong when China took it back from Britain in 1997.

How long will the airport be disrupted?

It's not clear. The protesters say they moved from the streets to the airport to bring their cause to an international audience. Over the weekend, demonstrators handed out leaflets in several languages, explaining their cause and their goals. They gathered in the terminals Monday and Tuesday, and vowed to return Wednesday.

An anti-extradition-bill protester offers an apology to passengers blocked from entering the security gates during the airport demonstrations. (Tyrone Siu/Reuters)

What is Air Canada doing to help travellers?

Air Canada says that if you bought a ticket no later than Aug. 11 for travel between Aug. 12 and Aug. 15, you can rebook your ticket to travel by Aug. 20 with no penalty. You can also rebook if your travel itinerary includes a flight to or from Hong Kong during the affected period. If you rebook to travel after Aug. 20, any fare difference will apply.

The airline says if tickets were booked through Aeroplan or Air Canada Vacations, travellers should contact those companies directly.

It also advises people travelling to and from Hong Kong International Airport to arrive at the airport at least six hours before their flight's scheduled departure to allow for extra time to check in and go through security.

What about other airlines?

Cathay Pacific, Hong Kong's main airline, told its customers to suspend all non-essential travel out of the city Aug. 13 and 14 and not even bother going to the airport. It also advised travellers to check their flight status and consult its flight delays and cancellation page for the most up-to-date information.

Cathay Pacific warned its employees they could be fired if they supported or took part in what the company called "illegal protests."

British Airways said customers booked to travel Aug. 14 or 15 could rebook their flight to a different date or get a full refund.

Other Chinese airlines have offered passengers wanting to avoid Hong Kong a free switch to nearby destinations, such as Guangzhou, Macau, Shenzhen or Zhuhai.