A Boeing 767 passenger aircraft of Delta Air Lines arrives from Dublin at JFK International Airport in New York as the Manhattan skyline looms in the background on Feb. 7, 2024.Delta Air Lines said Monday that it will bring its premium economy service to transcontinental flights in September, its latest attempt to boost sales of higher priced tickets to customers willing to splurge for more space and perks.Premium economy is a relatively new class of service that major airlines offer on longer, mostly inter ...