The 32-year-old already has a statue, a museum and a hotel named for him in Madeira.
"You know how proud I am of my roots, my homeland," Ronaldo, wearing a dark suit and tie, said in a speech.
The four-time player of the year has made a record 138 national team appearances for Portugal and is the team's top scorer with 71 goals.
The change was decided by the Madeira regional government after Portugal won the 2016 European Championship. Critics said a more distinguished historical figure would be more appropriate. Petitions were started for and against the change.
Ronaldo acknowledged that it was rare for a public figure to be honored while still alive, saying he was aware that some people didn't agree with the name change.
However, President Marcelo Rebelo de Sousa said the tribute was legitimate because it was decided by an elected government.
Ronaldo, Rebelo de Sousa said in his speech, is "an example of excellence" and "projects Madeira and Portugal across the world far more than anybody else."
Ronaldo is not the first soccer player with his name on an airport. In Northern Ireland, an airport was renamed George Best Belfast City Airport in 2006, a year after the local player and former Manchester United winger died.
In Funchal, the regional government provided transport to the outdoor ceremony for schoolchildren and elderly people at care homes. Also present were players and officials from the local Andorinha soccer club, where Ronaldo started when he was 7 years old.
Tourism is the economic mainstay of Madeira, which lies about 500 kilometres off the northwest coast of Africa. About 2.5 million passengers use the airport annually. The terminal is a low, two-story building next to an oceanside runway where landings are famous for sometimes being hairy because of crosswinds.
- With AP
