MileIntelKey Takeaways
- United MileagePlus is part of Star Alliance; Delta SkyMiles is part of SkyTeam. If you fly internationally, your alliance determines your partner airline options.
- United MileagePlus offers 5 elite tiers (Premier Silver, Premier Gold, Premier Platinum); Delta SkyMiles offers 4 (Silver Medallion, Gold Medallion, Platinum Medallion).
- Both share 1 transfer partner — you can earn flexibly and transfer to whichever program offers better value for a given trip.
- Choose United MileagePlus if you're among frequent domestic US travelers and Star Alliance flyers based at United hubs (ORD, EWR, IAH, SFO, DEN). Choose Delta SkyMiles if you're among travelers in Delta hub cities (ATL, MSP, DTW, SEA, SLC, JFK, LAX, BOS).
Quick comparison
| Category | United MileagePlusUnited Airlines | Delta SkyMilesDelta Air Lines |
|---|---|---|
| Alliance | Star Alliance | SkyTeam |
| Currency | miles | miles |
| Earn Rate | 5 base miles per $1 on eligible United flights. Elite bonuses: Silver +40%, Gold +60%, Platinum +80%, 1K +100% | 5 base miles per $1 on Main Cabin+ fares. Elite bonuses: Silver +2, Gold +3, Platinum +4, Diamond +6 miles per $1. Basic Economy does not earn miles |
| Avg ValueTie | 1.2¢ per mile | 1.1¢ per mile |
| Elite TiersTie | Premier Silver, Premier Gold, Premier Platinum, Premier 1K, Global Services | Silver Medallion, Gold Medallion, Platinum Medallion, Diamond Medallion |
| ExpirationTie | Miles do not expire as long as the account is open and in good standing | Miles never expire as long as the account is active and in good standing |
| Transfer PartnersTie | Marriott Bonvoy, Chase Ultimate Rewards | Amex Membership Rewards, Marriott Bonvoy |
| Best For | Frequent domestic US travelers and Star Alliance flyers based at United hubs (ORD, EWR, IAH, SFO, DEN) | Travelers in Delta hub cities (ATL, MSP, DTW, SEA, SLC, JFK, LAX, BOS) |
Elite Qualification Comparison
United MileagePlus
United uses PQF (flights) + PQP (spend), or PQP-only. The dual path matters: if you fly 60+ segments a year, you only need $22,000 PQP for 1K instead of $28,000 PQP-only. That's a $6,000 difference.
Credit card spend contributes PQP: the United Explorer card earns 500 PQP per $12,000 spend. The United Club Infinite card is better at 1,000 PQP per $12,000 spend. The United Quest card earns 500 PQP per $12,000 spent. Stack multiple cards to accelerate qualification.
Delta SkyMiles
Delta's MQD-only model is the simplest in the industry. Every dollar spent on Delta flights, Delta Vacations, and eligible purchases counts toward your MQD threshold. No segments, no points, no dual paths.
The Amex MQD Headstart is the key accelerator: Delta Platinum Amex gives $2,500 MQD Headstart, Delta Reserve gives $5,000 MQD Headstart (and the two types stack — holding both means $7,500 before your first flight). Additional MQD Boost comes from card spending throughout the year.
Upgrade Instruments
United MileagePlus
- PlusPoints
- United's flexible upgrade currency. Can be used for confirmed upgrades (applied at booking or up to departure) on United-operated flights. Points required vary by route: 20 for domestic, 40 for short-haul international, 80 for long-haul international Polaris. Unused PlusPoints roll over if you requalify at the same tier.
- Complimentary Upgrades
- Free upgrades to Economy Plus and domestic first/business class. Clears based on status, fare class, and check-in time. 1K clears most domestic flights; Silver may only clear on off-peak routes.
- GPU (Global Premier Upgrades)
- Systemwide upgrade instruments for international Polaris business class. These are legacy instruments that United has largely replaced with PlusPoints, but some 1K and GS members still receive them.
Delta SkyMiles
- Regional Upgrade Certificates (RUCs)
- Upgrade to First/Delta One on domestic and short-haul international flights (under 2,500 miles). Can be applied at booking for confirmed upgrade or waitlisted. Platinum gets 4, Diamond gets 8 as a Choice Benefit option.
- Global Upgrade Certificates (GUCs)
- Upgrade to Delta One on any Delta-operated flight worldwide, including long-haul international. The most valuable upgrade instrument in the Delta ecosystem. Diamond gets 3 as a Choice Benefit option.
- Complimentary Upgrades
- Free upgrades to Comfort+ and First Class on domestic flights, cleared based on Medallion status, fare class, and check-in time. Diamond members clear most domestic flights; Silver clears sporadically on off-peak routes.
- Mileage Upgrades
- Pay miles + a co-pay to upgrade on select domestic flights. Available to all SkyMiles members, not just elites. Costs vary by route.
Best Redemption Sweet Spots
United MileagePlus
- US to Japan (e.g., SFO-NRT)ANA Business Class via Star Alliance · 88,000 miles round trip
- ANA's 'The Room' business class is one of the best products in the sky. Booking via United miles on ANA-operated flights can still offer excellent value.
- US to Europe (e.g., EWR-FRA)Lufthansa Business Class · 77,000 miles one-way (dynamic)
- Lufthansa's new Allegris business class suite is rolling out in 2025-2026. Book with United miles for access to what will be one of Europe's best business products.
- US domestic (e.g., SFO-EWR)United Polaris / domestic first · 20,000-30,000 miles one-way
- On transcontinental routes, United flies wide-body aircraft with Polaris seats. This is lie-flat domestic business class for 20K-30K miles.
Delta SkyMiles
- US domestic short-haulDelta First Class · 10,000-15,000 miles one-way
- Delta domestic first on short routes (under 2 hours) can price at Flash Sale levels during off-peak. The hard product is standard recliner but the service is excellent.
- US to Europe (e.g., JFK-AMS, ATL-CDG)Delta One · 50,000-85,000 miles one-way
- Delta One suites on the A350 and A330-900neo are competitive with any business class. Award availability is better than United Polaris on high-demand routes.
- US to Latin AmericaDelta One / First · 30,000-50,000 miles one-way
- Delta's Caribbean and Latin American network is strong from ATL and JFK. Miles often price lower than competitors on these routes.
Credit Card Strategy
United MileagePlus
The United Club Infinite card ($525/year) is the power play: United Club access, 2 free checked bags, 1,000 PQP per $12,000 spend, and 500 PlusPoints per $50,000 spend. The PlusPoints alone make it worthwhile for Platinum+ members.
Chase Sapphire Reserve ($550/year) earns Chase Ultimate Rewards that transfer 1:1 to United. The 3x on travel and dining often yields better earn rates than United's co-branded cards for non-United spending.
Delta SkyMiles
Delta Reserve Amex ($650/year) is the cornerstone: $5,000 MQD Headstart, Sky Club access on Delta flights, and Centurion Lounge access. The MQD Headstart alone can save you $5,000 in flights toward status.
Stack with Delta Platinum Amex ($350/year) for an additional $2,500 MQD Headstart = $7,500 total before flying. Add MQD Boost from card spending throughout the year.
Choose United MileagePlus if you...
- Avg Value
- 1.2¢
- Elite Tiers
- 5
Frequent domestic US travelers and Star Alliance flyers based at United hubs (ORD, EWR, IAH, SFO, DEN). United Airlines' loyalty program offering miles for flights, upgrades, and partner purchases across the Star Alliance network.
Skip if:Travelers who fly primarily Delta or American routes — status on your most-flown carrier always beats cross-carrier optimization
Choose Delta SkyMiles if you...
- Avg Value
- 1.1¢
- Elite Tiers
- 4
Travelers in Delta hub cities (ATL, MSP, DTW, SEA, SLC, JFK, LAX, BOS). Delta Air Lines' loyalty program with MQD-only elite qualification. Miles never expire and the domestic network is one of the strongest in the US.
Skip if:International travelers who want Star Alliance or OneWorld partner awards — Delta's SkyTeam network is narrower
Frequently Asked Questions
It depends on your travel patterns and home airport. United MileagePlus is best for frequent domestic US travelers and Star Alliance flyers based at United hubs (ORD, EWR, IAH, SFO, DEN). Delta SkyMiles is best for travelers in Delta hub cities (ATL, MSP, DTW, SEA, SLC, JFK, LAX, BOS). The right program is the one that matches your most-flown routes and travel style.
United MileagePlus: Miles do not expire as long as the account is open and in good standing. Delta SkyMiles: Miles never expire as long as the account is active and in good standing.
While you can't transfer directly between United MileagePlus and Delta SkyMiles, they share transfer partners through credit card programs, which can serve as a bridge between the two ecosystems.
United MileagePlus offers 5 tiers (Premier Silver, Premier Gold, Premier Platinum, Premier 1K, Global Services). Delta SkyMiles offers 4 tiers (Silver Medallion, Gold Medallion, Platinum Medallion, Diamond Medallion). The comparison depends on which benefits matter most to you — read the detailed tier breakdown above.
Yes — if you have balances in both programs, MileIntel can track them side by side and recommend which program's miles to use for each specific trip. The right program can change based on your route, cabin, and what upgrade instruments you have available.
MileIntel is an independent tool and is not affiliated with, endorsed by, or sponsored by any airline or loyalty program mentioned on this page. All trademarks belong to their respective owners.
