The vintage planes had taken off from Sudan for the three-hour flight into Ethiopia - Getty Images
A group of international pilots taking part in a vintage plane rally have landed in Kenya after being freed from detention in Ethiopia, organisers say.
About 20 aircraft had been impounded at the airport in Gambela, western Ethiopia, after crossing "illegally" into the country from Sudan.
But the aviators, on a mission to travel the length of Africa, resumed their journey on Thursday.
One of the released pilots failed to arrive at the destination.
British pilot Maurice Kirk, 72, had already been reported missing once but was later found to be among the pilots detained in Ethiopia.
In a Facebook post, Vintage Air Rally said: "For the second time in two flights, Maurice is a no show. We have launched (again) an overdue aircraft process (now Kenyan rather than Ethiopian)."
Vintage Air Rally spokesman Jeremy Martin told the BBC that Mr Kirk was "officially off the rally but since we know he's out there we can't leave him".
The head of Ethiopia's civil aviation authority, Wosenyele Hungnall, told the BBC that the aircraft had crossed illegally into Ethiopian airspace from Sudan.
Ethiopia is currently under a state of emergency following a recent upsurge in violent attacks, and there is a military presence in Gambela because of tensions with neighbouring South Sudan.
The rally was suspended while diplomats tried to secure the release of the pilots and crews.
On Thursday, Vintage Air Rally said the pilots were free to continue their journey to South Africa.
Participants, from 13 different countries, are attempting to cover 13,000km (8,000 miles) using biplanes built between the 1920s and 1940s, and support aircraft.
The planes date from the 1920s and 1930s - AFP
The planes took off for Cape Town from the Greek island of Crete on 12 November.
The aviators aim to cross 10 countries while making 37 stops in the month-long journey.