Authorities in Somalia have summoned Kenya's ambassador to the capital Mogadishu to protest against what it said was a violation of its airspace.
An aircraft from Nairobi landed in the southern Somali port city of Kismayo on 5 October despite restrictions put in place by the Somali authorities.
The government had ordered that all flights to Kismayo must pass through Mogadishu for clearance.
Somalia's Foreign Minister Abdikadir Ahmed called the incident an "encroachment":
The directive was sparked by a row with the leader of the regional state of Jubaland, Ahmed Mohamed Islam alias Madobe – an ally of Kenya – who has governed the state since 2013.
He recently won a fourth term in an election dismissed by authorities in Mogadishu.
Kenya sees him as a key player in its military operation against militant Islamist group al-Shabab in the region that shares its border.
Kenya is planning to send a delegation to Mr Islam's inauguration which is expected to be held on Sunday.
Somalia's government eased the flight restriction to allow former Somali presidents Hassan Sheikh Mohamud and Sheikh Sharif Sheikh Ahmed to land in Kismayo.