Found this tonight while messing around on the internet. I think "Delta Is Ready When You Are" is what I grew up hearing just about every day of my life.

Post 2005 nothing more is mentioned. I think "Change Is..." has got to be in there somewhere, right?

The List:

Speed, Comfort and Safety (1929)

Delta Air Lines - The Trans-Southern Route (1935)

Speed, Comfort and Convenience (1930s)

The Airline of the South (1940)

None Faster—None Finer—To and Through the South (1948)

Hospitality and Service from the Heart (late 1950s)

Delta—One of America's Pioneer Scheduled Airlines (1950s)

DELTA the airline with the BIG JETS (1959)

DELTA Best Thing That Ever Happened to Air Travel (ca. 1966-1968)

Delta Is Ready When You Are (1968-Dec 1984)

That's the Delta Spirit

DELTA. The Airline Run by Professionals. (1970)

Delta Is My Airline (1974)

Airlines Are the Same; Only People Make the Difference (1980)

Delta Gets You There (1984-1987)
other versions: Delta Will Get You There and Delta Gets You There with Care

We Love to Fly and It Shows (Sep 1987)

Ready When You Are (ca. 1992)

You'll Love the Way We Fly (1994)

On Top of the World (1997)

Good goes around (Jan 2005)