Delta Air Lines cut its profit forecast for 2026 on Friday, saying its fuel bill will rise by about $6 billion this year. The Atlanta-based airline now expects adjusted earnings of $5.10 to $5.60 a share, down from the $6.50 to $7.50 it forecast in July.

"All of it's fuel," Chief Financial Officer Erik Snell told reporters when asked what drove the cut, Reuters reported.

The summer quarter shows why. Delta spent $4.1 billion on fuel from July through September, up 62% from a year earlier, and paid $3.61 a gallon after its July plan had assumed about $3.15. The company said that gap cost it more than $500 million beyond what it expected.

Delta earned $1.72 a share on an adjusted basis, below analyst estimates and below the $2.00 to $2.50 range the airline gave in July. Counting one-time items, it earned $1.15 a share. CNBC said it was the airline's first earnings miss in two years. The shares fell in premarket trading, down 3% according to Reuters and more than 4% according to Yahoo Finance, in reports published around 6:30 a.m. ET.

Travelers kept flying anyway. Adjusted revenue reached a record $17.6 billion for the quarter, up 16% from a year earlier, and premium cabin sales grew 18%. Chief Executive Ed Bastian told CNBC that fares keep rising and that "the consumer response continues to be quite strong."

Those fares are part of the story. U.S. airfares rose about 25% from a year earlier in the five months through August, Reuters reported, citing federal price data.

The pressure is not over. Delta expects fuel to cost about $4.25 a gallon in the final three months of the year, even after help from its own refinery near Philadelphia. It expects to earn $1.15 to $1.65 a share in that quarter, with revenue up about 20%, and it cut its free cash flow outlook to about $2.5 billion from a range of $3 billion to $4 billion.

This is the second fuel shock of the year for Delta. In the spring quarter, it paid $3.93 a gallon in what it called the highest quarterly fuel expense in its history, yet still earned $1.56 a share and kept its full-year forecast in place.

Delta is the first big U.S. airline to report results for the summer quarter. United, American and Southwest report later this month.

What we know: Delta cut its 2026 forecast because fuel costs ran far above its summer plan.
What we don't: How long fuel prices stay high, and how much further fares can rise before travelers start to pull back.