The actress providing the voice over work in the Delta commercials “4 a.m.” from 2017 is:
Viola’s IMDB Page
Viola is a Golden Globe winning, Emmy Winning and Oscar nominated (potentially Oscar Winning) actress known for her roles the movies The Help, Doubt, and Fences. Viola also starred in the television series How to Get Away with Murder.
Viola has been providing the voice over for Delta since 2017, previously Donald Sutherland provided the Delta voice over work.