Question: Who sang i'll fly away in o brother where art thou?
Disambiguated questions and answers: question: Who sang i'll fly away on o brother where art thou's original soundtrack album?
Who sang i'll fly away in o brother where art thou's film?
Who sang i'll fly away on o brother where art thou's 10th Anniversary delux edition bonus disc?
answer: Alison Krauss, Gillian Welch
Gillian Welch
Alison Krauss
Kossoy Sisters with Erik Darling
Kossoy Sisters
Erik Darling
Erik Darling and The Kossoy Sisters
Erik Darling
The Kossoy Sisters
Natural Questions answer: Alison Krauss
Gillian Welch (from the Wikipedia article "O Brother, Where Art Thou? (soundtrack)")