Story updated at 4:35 p.m. with Thursday market close information
Shares of Delta closed down -5.4% to $38.50, and were falling -0.2% to $38.42 in after-hours trading.
Lufthansa said it now expects an operating profit of about 1 billion euros for 2014, down from previous estimates of 1.3 billion to 1.5 billion euros. The lower forecast is due to increased competition from Gulf airlines that are hurting the airline's U.S. and European businesses.
Must read: Warren Buffett's 25 Favorite Stocks
TheStreet Ratings team rates DELTA AIR LINES INC as a Buy with a ratings score of B. TheStreet Ratings Team has this to say about their recommendation:
"We rate DELTA AIR LINES INC (DAL) a BUY. This is driven by several positive factors, which we believe should have a greater impact than any weaknesses, and should give investors a better performance opportunity than most stocks we cover. The company's strengths can be seen in multiple areas, such as its notable return on equity, reasonable valuation levels, solid stock price performance, compelling growth in net income and revenue growth. We feel these strengths outweigh the fact that the company shows weak operating cash flow."