All jazz improvisers prepare certain licks and patterns ahead of time. It would be impossible to do a coherent-sounding improvisation without an extensive repertoire of well-rehearsed scales, arpeggios and phrases. read more
It sounds quite different to perform a learned score than it does to improvise. I have no idea whether Ella worked entire scats out in advance or not, but I doubt it. She did have certain signature motifs and ideas that she re-used over and over with minor variations, as every jazz musician does. read more
My answer: Start with Ella Fitzgerald Sings the Cole Porter Songbook on Verve Records/CD - some is on YouTube; 2nd: Ella Fitzgerald Sings the Duke Ellington Songbook also Verve; 3rd: Ella Sings the Rogers & Hart Songbook, also Verve. read more
Sarah Vaughan, Ella Fitzgerald, Mel Tormé, and Billy Eckstine—who came out of the bands and embarked on full-time careers as highly paid “single” acts. read more