When a flight is listed as "Delta operated by Air France," it refers to a codeshare agreement between the two partner airlines. In this scenario, you purchased your ticket through Delta Air Lines (the marketing carrier), but the actual physical flight, the aircraft, and the cabin crew are provided by Air France (the operating carrier). This means that while you may have a Delta flight number on your itinerary, you will likely need to check in at the Air France counter at the airport and fly on an Air France plane, such as an Airbus A350 or Boeing 777. The in-flight service, including meals and amenities, will follow Air France's standards rather than Delta's. This partnership allows airlines to offer more destinations and seamless connections within the SkyTeam alliance. It is important to check your baggage allowance and check-in procedures, as they are typically governed by the operating carrier (Air France) rather than the airline that sold you the ticket.