Actually we are still Delta Air Lines, Inc.
Our brand image now reflects the company name as Delta.
But when you refer to the company by its full name it is Delta Air Lines. I like it, as it is a throwback to the days when most airlines had the word "airlines" written as two words. I even find it somewhat annoying when people get it wrong and write Delta Airlines.
Similarly, the old giant neon sign on the side of United's SFO Maintenance Operations Center building has "UNITED AIR LINES" written on it.
It's a new day. Every moment matters. Now, more than ever.