Nairobi - Kenyan police fired tear gas at opposition leader Raila Odinga's car, a Reuters witness said.
Earlier, police and supporters of Odinga had fought running battles on Friday along the main road to Nairobi's international airport before Odinga landed from an overseas trip.
Odinga has called for a "National Resistance Movement" to protest the outcome of a repeat presidential election, which was ordered by the Supreme Court after it annulled the results of an August poll over procedural irregularities.
Police fired into the air to disperse hundreds of people gathered outside Jomo Kenyatta International Airport who were waiting for Odinga to return from an overseas trip, a Reuters photographer said.
In what is seen as the last chance for legal scrutiny of the vote, the court will rule on Monday on cases that seek to nullify the rerun election. The political crisis has stirred fears for the stability of the east African nation, a regional hub for trade, diplomacy and security.
In Friday's violence, people threw stones at the police and threw up burning barricades on Mombasa Road, the highway that links Nairobi's downtown business district and the airport.
Despite a partial police ban on protests in the capital, demonstrators had gathered in the morning near the airport to wait for Odinga's return. Police checked vehicles headed from the city centre to the airport in another attempt to stop the demonstration from building.
Kenyan TV channels broadcast footage of what they said was Odinga's motorcade leaving the airport after he landed just before midday. Motorcycle taxi drivers and people on foot shouted their support as the motorcade moved toward downtown.
President Uhuru Kenyatta won a second, five-year term with 98 percent of the vote in the repeat election after Odinga boycotted the contest. Only 39 percent of registered voters took part.
In Monday's Supreme Court rulings, judges could order a fresh vote or clear the way for the incumbent to be sworn in for his second term. If the election is upheld, Kenyatta will be sworn in on Nov. 28.
Dozens of international flights depart and arrive daily at Nairobi's main airport. The national airport authority said on its official Twitter handle just before midday that operations were running normally.
Kenya's prolonged election season has disrupted its economy. Human rights groups say at least 66 people have died in bloodshed surrounding the two elections.
Ahead of Monday's Supreme Court ruling, Kenya Airways' chairman told an investor briefing on Friday morning: "Hopefully we don’t have another presidential election so we can get on with life."