China has acted as a lifeline for North Korea's moribund economy as its largest trading partner and an important source of diplomatic and political support.

However, travel between the East Asian neighbours has been heavily restricted since 2020, when strict border closures were imposed during the Covid-19 pandemic.

Flight CA121 departed Beijing Capital Airport at 7:58 am (2358 GMT on Sunday), according to FlightStats data, and is scheduled to arrive at Pyongyang's Sunan International Airport at 11:00 am (0200 GMT), according to Air China's website.

Travellers at Beijing's bustling airport formed a snaking queue to check in their luggage with the airline, AFP journalists saw.

Pyongyang's continued reluctance to issue tourist visas means only travellers with official or other special purposes can make the cross-border journey.

Pyongyang-bound business traveller Zhao Bin showed reporters his air ticket, and expressed optimism that tourism would resume for Chinese visitors.

"I expect both railway routes and Air China flights will increase, and there will be more exchanges and travel between people," he said.

Economy class tickets were available for around $200, AFP saw, and a return flight from Pyongyang is scheduled for midday.

Daily passenger train services resumed this month with China, the main source of most foreign travellers to North Korea.

But AFP journalists in China's northeastern town of Dandong -- which has long been a key gateway for exchanges with North Korea -- saw a mostly empty daily passenger train travelling into the isolated nation last week.

China has fully reopened its borders since the pandemic, but North Korea has proceeded more slowly.

North Korea resumed direct flights and train services with Russia last year and state carrier Air Koryo restarted flights between Beijing and Pyongyang in 2023.

Young Pioneer Tours, which specialises in travel to North Korea, told AFP in March that Air China resuming its route to Beijing opens Pyongyang up to more accessible connections.

"Previously, Air China also operated flights on Wednesdays and Fridays, so there is a possibility that additional services could be added again in the near future," Young Pioneer tour manager Rowan Beard said.

While the announcement of flights was "promising" for tourism, "there is still no further confirmation regarding Western tourists", Beard added.