The United Nations has listed Yemen as the world's number one humanitarian crisis (AFP)
UN officials are in talks with the coalition to get permission for the flights to deliver aid to Yemen, where some seven million people are on the brink of famine.
"There were no flight clearances granted to our flights today," said UN spokesman Farhan Haq. "We expected to have two flights going and those are on hold for now."
The move follows the interception of a missile fired towards Riyadh on Saturday, which the coalition has described as a "dangerous escalation" by the Houthi militia that controls large parts of Yemen.
The coalition and US President Donald Trump have both blamed Iran for the attack, but the head of Iran's Revolutionary Guards denied the accusations on Sunday, rejecting Trump's remarks as "slanders".
The Saudi-led Arab military coalition intervened in Yemen in 2015 to support President Abedrabbo Mansour Hadi after the Houthis forced him into exile.
The coalition have been regularly criticised by the UN for blocking aid to civilians.
The United Nations has listed Yemen as the world's number one humanitarian crisis, with 17 million Yemenis in need of food, seven million of whom are at risk of famine and cholera causing more than 2,000 deaths.
In late October, UN aid chief Mark Lowcock voiced alarm at the "shocking" humanitarian conditions in conflict-hit Yemen and called on warring parties to respect international law.
"I came to Yemen to better understand the deteriorating humanitarian crisis, including the fastest-growing cholera epidemic the world has ever seen, the world's largest food insecurity and conditions of widespread population displacement," Lowcock said.
"It's been shocking to see the terrible impact of this man-made conflict," he told reporters before leaving Sanaa.
"The UN calls on all parties... to uphold the highest standards of international humanitarian law and respect human rights with respect to everyone including detainees and journalists," he added.
Last month, the United Nations put the Saudi-led coalition on its blacklist for killing and maiming 683 children during the conflict in 2016 and for carrying out 38 verified attacks on schools and hospitals.
The civil war has killed more than 10,000 people and triggered a severe humanitarian crisis in one of the Arab world's poorest nations.