The Turkish leader was visiting the Teknofest air show on Saturday at Istanbul's old Atatürk airport, an event that showcases the military's drones and aircraft.
Erdogan has governed the country for two decades. He is seeking a third presidential term in Turkey's 14 May elections. The head of state is due to take part in an election rally in Izmir, on the west coast, later Saturday, according to his official programme.
He is also expected in the capital Ankara on Sunday, exactly two weeks before the first round of voting, to resume his election campaign after a four-day break this week.
Erdogan spoke by phone Friday with UN Secretary-General Antonio on several matters, including the Ukraine-Russia grain and fertiliser deal they helped arrange, UN spokesman Stephane Dujarric said. He said they discussed “how to guarantee the improvement, expansion and extension” of the deal, which expires 18 May.
Erdogan became ill during a TV interview on Tuesday evening with what Health Minister Fahrettin Koca later said was a “gastrointestinal infection”. His election rallies planned for Wednesday and Thursday were cancelled.
He looked pale Thursday as he inaugurated a nuclear power plant via video in his first public appearance since his illness. During his Friday video address, Erdogan seemed well as he spoke for about 10 minutes from behind a desk.
Other officials sought to dispel concerns over the 69-year-old leader's health before the presidential and parliamentary elections. Recent polls showed a slight lead for Erdogan’s main challenger amid an economic downturn and a devastating February earthquake that killed more than 50,000 people.
Erdogan, who underwent intestinal surgery in 2011, has ruled Turkey since 2003, first as prime minister and as president since 2014. He campaigned hard in recent weeks, attending several events across the country every day.