Jet fuel costs have plunged. Here’s why Delta says cheaper flights aren’t on the way

By Chris Isidore, CNN (CNN) — Air fares aren’t coming down, Delta Air Lines said Friday, even though the cost of jet fuel has fallen sharply. In its second-quarter earnings report, the airline said its various measures of fares are up 11%-12% due to strong demand for travel, and that it sees “sustainability” in those