Envoy Martin Griffiths was expected to hold talks with Yemen's Huthi rebels in Sanaa, the UN source told AFP on condition of anonymity, ahead of potential negotiations in Sweden this month aimed at ending nearly four years of war in the Arab world's poorest country.
A Saudi-led military coalition allied with the Yemeni government against the Iran-backed Huthis announced it would allow for the evacuation of wounded rebels on a UN chartered plane Monday.
The decision is a key step in kickstarting stalled negotiations, as world powers press for an end to the conflict that has pushed Yemen to the brink of famine.
The United Nations source told AFP the reopening of Sanaa international airport, controlled by the rebels and largely destroyed by Saudi-led air raids, was a priority at the planned peace talks.
Saudi Arabia and its allies control Yemen's maritime borders and airspace and have severely restricted imports to the country, where the UN warns 14 million people risk starvation.
The alliance accuses the Huthis of smuggling arms from Iran through Sanaa airport and Yemen's many ports.
Yemen's Huthi rebels announced at the weekend that Sanaa international airport could now meet the requirements of the International Civil Aviation Organization (ICAO) to "receive civilian flights".
The ICAO has not released a statement on Sanaa airport.
A UN panel of experts this year said the "effective closure" of Sanaa airport since 2015, when the Saudi-led alliance intervened in the Yemen war, constituted a violation of international humanitarian law.
More than 10,000 people have been killed since the Saudi-led coalition joined the Yemen war in an attempt to bolster President Abedrabbo Mansour Hadi's standing against the rebels, who had seized the capital and a string of ports in a takeover the year before.
Multiple UN-sponsored attempts to find a solution to the Yemen conflict have failed.
UN envoy Griffiths had initially announced Sanaa international airport would reopen in September, when the rebels and government were due in Geneva for talks.
The talks fell through before they began, as the rebels refused to leave Sanaa unless the UN could guarantee the evacuation of wounded fighters and the safe return of their delegation from Switzerland.