Delta Air Lines (DAL) 10-Q 2018 Q2 Quarterly report

Exhibit 15

July 12, 2018

The Board of Directors and Stockholders of

Delta Air Lines, Inc.

We are aware of the incorporation by reference in the Registration Statements (Form S-3 No.’s 333-206258, 333-209571, and 333-216463, and Form S-8 No.’s 333-142424, 333-149308, 333-154818, 333-151060, and 333-212525) of Delta Air Lines, Inc. for the registration of its securities of our report dated July 12, 2018 relating to the unaudited condensed consolidated interim financial statements of Delta Air Lines, Inc. that are included in its Form 10-Q for the quarter ended June 30, 2018.

/s/ Ernst & Young LLP