Can anyone identify this song?

It's a song with no words - only a lilting, melodic whistling. It sounds like it would be something vaguely Hawaiian in tone and that it would date from the 1950s or 1960s. It is currently in use in some VISA check card commercials and was used in a and the City episode (which specific episode I can no longer recall, but I feel as if the the song was used in conjunction with scenes shared by the Carrie Bradshaw and Mr. Big characters). Can someone help me out?