Delta says cheaper flights won’t come anytime soon. Here’s why

(CNN) - Jet fuel prices are down, but many airfares remain high.

The head of Delta Air Lines is blunt about why.

CEO Ed Bastian told CNBC that air travel demand remains strong and that supply and demand drive airfares.

Delta’s second-quarter earnings report showed its airfares rose 11% to 12%.

At the same time, amid the Iran war, fuel prices for the airline spiked 75% from a year earlier.

But Delta projects its fuel costs will be down 20% this quarter.

Bastian said current airfares are sustainable.

Other airlines are also keeping airfares higher.