The UN's World Programme Programme (WFP) said its food airlift to the Somali capital Mogadishu for drought victims was delayed on Tuesday due to last minute bureaucratic hurdles in Kenya.
"The aircraft are loading with the hope that they can take off on Wednesday," said WFP spokesman David Orr.
"This will be the first of series of flights -- once they start, they will just keep coming and coming in an ongoing operation," he added.
The flights have only a narrow timeframe to fly, offload their critical cargo and then return to Nairobi, Orr added, and a wait for clearance permission in Nairobi delayed the mission.
An estimated 3.7 million people in Somalia -- around a third of the population -- are on the brink of starvation and millions more in Djibouti, Ethiopia, Kenya and Uganda have been struck by the worst drought in the region in 60 years.