American Airlines offers the most nonstop options from Dallas/Fort Worth International Airport (DFW) to Philadelphia International Airport (PHL) in December due to its DFW hub status; expect competitive schedule choices, Main Cabin and premium cabins, and AAdvantage benefits. Delta and United may offer competitive connecting itineraries through their hubs (ATL, DTW, ORD), sometimes with lower fares but longer travel times. Low-cost carriers may appear on multi-leg itineraries but rarely offer nonstop service on this route. For frequent travelers, factor in loyalty program status, baggage allowances, and change policies when choosing a carrier. CTA: Compare seat availability and loyalty perks now to pick the best December airline for your DFW–PHL trip.