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Shares of Delta Air Lines Inc. (DAL - Get Report) slipped 4.85% to close at $53.55 Thursday after the Atlanta-based carrier's 2019 profit forecast fell short of expectations.

During a meeting with investors, Delta said it will report a profit of $6 to $7 per share next year. The lower end of the forecast fell short of Wall Street's expectations of $6.70 per share.

CEO Ed Bastian said Delta would continue segmenting its cabins with an increased focus on higher-margin premium products, which now account for 30% of Delta's revenue stream, or twice the amount from six years ago. He said travel demand remains solid.

Delta plans to increase average seats per aircraft by 2% annually between 2018 and 2023, with premium seats increasing by 40% on every aircraft.

The airline said it expects a $300 million drop in oil prices in 2019. Oil prices registered the steepest monthly decline since 2008 in November.

Delta expects to increase capacity by 3% next year. In January, United Continental Holdings (UAL - Get Report) said it wants to increase capacity by 4 to 6% through 2020. In addition, Delta said it expects $3 billion to $4 billion in free cash flow and about $4.5 billion in capital expenditures.

Other airlines were feeling the heat Thursday: Southwest Airlines (LUV - Get Report) fell 1.20 to $50.29; United Continental Holdings fell 2.89% to $87.04; JetBlue Airways (JBLU - Get Report) slipped 2.32% to $17.24; and American Airlines Group (AAL) lost 4.57% to $32.78.