Delta operates a larger fleet (900+ aircraft vs 850+) and maintains slightly higher on-time performance (83% vs 81%), while United offers more international routes (350+ destinations vs 325+) and competitive pricing on premium economy seats. Both are major US carriers with similar safety records and frequent flyer programs.
Delta Air Lines vs United Airlines — Side-by-side comparison on A Versus B
Choose Delta if you prioritize reliability, on-time performance, and domestic connectivity with solid customer satisfaction scores. Choose United if you need extensive international coverage, more frequent flights to European and Asian hubs, and don't mind slightly lower punctuality ratings. Both offer comparable pricing and frequent flyer benefits, making the choice dependent on your route preferences and priority needs.
Compare Delta Air Lines vs United Airlines
Premium-positioned carrier known for operational excellence and reliability
Second-largest US carrier with strong international presence, hub-and-spoke operations across multiple US cities.
Customer Satisfaction Score (J.D. Power 2025)
Delta Air Lines vs United Airlines — Comparison Data
Structured comparison data for Delta Air Lines vs United Airlines with 198 attributes.
Premium Cabin Seat Pitch (Business/Polaris)
Average Domestic Round-Trip Ticket Price
Customer Satisfaction Score (J.D. Power 2024)
DOT Complaints Per 100,000 Passengers (2024)
J.D. Power Customer Satisfaction Score (2024)
Business Class Lie-Flat Seats (Long-Haul)
Baggage Delay Complaints (per 100,000 passengers)
Delta Air Lines vs United Airlines — Attribute Category Vocabulary
Taxonomy of attribute categories used to classify comparison data for Delta Air Lines vs United Airlines.
Is Delta or United Airlines more reliable?
Delta Air Lines is more reliable than United Airlines based on on-time performance and cancellation data from the US Department of Transportation. In 2024, Delta posted an 82.1% on-time arrival rate (ranked #2 among major carriers) vs. United's 79.8% (ranked #4). Delta also leads on baggage mishandling (2.3 per 1,000 passengers vs. United's 3.1) and passenger complaints (3.8 per 100,000 vs. United's 5.2). The reliability gap is real but not dramatic — the difference of 2-3 percentage points in on-time performance means that over 100 flights, Delta arrives on time about 2-3 more times than United. United has improved substantially since 2020 under CEO Scott Kirby's operational leadership, and its on-time performance is now competitive. J.D. Power's 2025 airline satisfaction study ranked Delta #1 among traditional carriers; United was #3.
Is United or Delta better for international flights?
The comparison depends on your departure city and destination. United has a structural advantage for international travel from the US East Coast — Newark (EWR) is United's largest international hub and offers more non-stop transatlantic and transpacific routes from the New York area than Delta's JFK hub. United's Star Alliance membership also provides better partner redemption options (Lufthansa, Singapore Airlines, ANA) for international award travel. Delta's SkyTeam alliance partners (Air France-KLM, Korean Air) are strong for Europe and Asia. For premium cabin quality: United's Polaris business class product has closed the gap with Delta One since 2022 — Polaris now features direct aisle access seats on most widebody aircraft, and multiple publications rate it as Delta One's equal or superior on comparable routes. Both airlines significantly surpass American Airlines in long-haul international premium cabin experience. If price is the primary factor, both airlines price international fares similarly, with competitive sales from their respective hubs.
Is SkyMiles or MileagePlus a better loyalty program?
United MileagePlus is generally rated a better program than Delta SkyMiles for frequent travelers in 2026, primarily for award redemption flexibility. MileagePlus miles can be redeemed on 35+ Star Alliance partners (Lufthansa, Singapore Airlines, ANA, Air Canada, etc.) with partner award pricing that can yield exceptional value for international business class — United partners like ANA and Singapore Airlines have historically offered first and business class redemptions at relatively low mile costs. Delta SkyMiles has its own award strengths (SkyTeam partner redemptions, Delta One availability) but has made award pricing less predictable with its dynamic pricing model since 2019. The 2024 SkyMiles restructuring (higher credit card spend thresholds for Medallion status, tighter SkyClub access) reduced the program's perceived value among Delta loyalists. MileagePlus miles never expire with any account activity in 18 months; SkyMiles never expire unconditionally — an advantage for infrequent travelers.
Which airline has better first class, Delta or United?
For domestic first class (US routes), Delta edges out United — the inflight experience (meal quality, service consistency, seat comfort on most mainline jets) gives Delta a slight advantage in J.D. Power and consumer review scores. For international business class (long-haul routes), United's Polaris product is highly competitive with Delta One and rated as equivalent or superior on some aircraft configurations. Delta One on widebody aircraft (A330, A350, B767, B757) features fully-flat beds with direct aisle access; Polaris on United's 787 and 767 features fully-flat beds with direct aisle access on alternating seats. The Delta One suite product (available on some A321XLR and A350 aircraft) offers a closing door for full privacy — a product United doesn't yet widely offer. Practically speaking, the "better" first class is often whichever airline has direct non-stop service to your destination — both Delta One and United Polaris are premium products that far exceed domestic first class in food, service, and seat quality.