Seattle/Tacoma International Airport (SEA) is located 14 miles South of Downtown Seattle and 21 miles north of Downtown Tacoma, within the city of SeaTac, in the state of Washington. It is one of Delta Airlines’ gateways to Asia and serves connecting flows to/from the Pacific Northwest and Alaska. It is currently Delta’s 7th-largest hub, based on data from April 2024 to April 2025. In the article below, we will look at the ins and outs of Delta’s Seattle hub from both its local dynamics to the need it fulfills for Delta itself.
About Seattle
As of the 2023 demographic numbers provided by data.census.gov, the Seattle-Tacoma-Bellevue metro area has 861,459 foreign-born residents. This makes it the 12th largest metropolitan area for foreign-born residents. Seattle’s largest immigrant groups by country are India, Mexico, China, the Philippines, and Vietnam. The Seattle-Tacoma-Bellevue metro area grew by 105,474 between 2018 and 2023, which represented a 2.6% population growth.
As of the end of 2023, the Seattle region had a GDP of $567 billion, which represented 14.6% growth between 2021 and 2023.
About Delta's Hub at Seattle
- Population within 100 KM of SEA: 5.07 million
- Total passenger count at SEA between April 2024 and April 2025: 50,815,274
- Total passengers carried by Delta and its regional subsidiaries: 12,349,600
- Percentage of traffic at SEA carried by DL: 24.3%
Destinations Served...
Presently, DL serves 48 domestic and 13 international destinations at SEA. Of those, 47 domestic and 11 international destinations are served year-round and at least four times a week.
Delta’s Overall Load Factor at SEA was 84.52% between April 2024 and April 2025. The highest LF routes from SEA on DL were (must have at least 36 yearly departures):
First the Highest...
- Detroit (DTW): 91.97%
- Minneapolis (MSP): 91.42%
- New York (JFK): 90.62%
- Atlanta (ATL): 90.48%
- Tampa (TPA): 89.85%
- Orlando (MCO): 88.72%
- Chicago (ORD): 88.48%
- Amsterdam (AMS): 88.42%
- Paris (CDG): 87.95%
- Cancun (CUN): 87.85%
...and the Lowest.
- Kansas City (MCI): 75.84%
- Lewiston (LWS): 75.10%
- London (LHR): 74.15%
- Redmond (RDM): 73.62%
- Portland (PDX): 72.80%
- Medford (MFR): 71.53%
- Taipei (TPE): 71.19%
- Palm Springs (PSP): 69.41%
- Ketchican (KTN): 69.01%
- Juneau (JNU): 60.57%
Connectivity
6,050 passengers connect at SEA on DL daily each way on average. Of those, 3,991 were making purely domestic connections, and 2,059 were making connections with an international component. These figures mostly represent Delta and its marketed flights, but also those that fly into SEA on another carrier to connect to Delta.
Fleet Breakdown at DL's SEA Hub
In April 2025, Delta averaged 150 departures a day from its SEA hub. Of these, 96 were mainline flights operated by Delta itself and 54 were operated by regional partners marketed by Delta. This makes a 64.0% Mainline operation.
Seattle as an O&D Market
Delta flies 10,736 O&D passengers from SEA daily, non-directional, averaged between April 2024 and April 2025 (PDEW).
- Of the 10,752 total O&D passengers, 9,312 passengers carried by DL to/from SEA are domestic O&D.
- Domestic O&D is up by 1,178 PDEW or 12.7% since 2019.
- Below are the largest domestic O&D markets carried by DL to/from SEA, daily averaged as of April 2025.
Domestic O&D to/from SEA by DL Hub...
- Los Angeles (LAX): 591
- New York (JFK): 475
- Atlanta (ATL): 472
- Minneapolis (MSP): 354
- Salt Lake City (SLC): 402
- Boston (BOS): 329
- Detroit (DTW): 321
...and by non-DL Hub.
- Phoenix (PHX): 478
- Las Vegas (LAS): 463
- San Diego (SAN): 431
- San Francisco (SFO): 278
- Orlando (MCO): 259
- Santa Ana (SNA): 252
- Chicago (ORD): 246
- Denver (DEN): 212
- Honolulu (HNL): 182
- Austin (AUS): 181
- San Jose (SJC): 177
- Boise (BOI): 162
- Ontario (ONT): 144
- Fort Lauderdale (FLL): 138
- Sacramento (SMF): 136
- Washington DC (IAD): 135
- Spokane (GEG): 131
- Tampa (TPA): 126
- Raleigh (RDU): 118
- Cincinnati (CVG): 111
- DL carries 1,440 international O&D passengers daily, averaged, non-directional, to/from SEA.
- This is up by 335 PDEW or 23.3% since 2019.
- Below are the largest international O&D markets to/from SEA by passengers carried by DL.
Top International Leisure Destinations by O&D...
- Cancun (CUN): 110
- San Jose del Cabo (SJD): 73
- Puerto Vallarta (PVR): 71
....and top non-Leisure based International Destinations.
- Tokyo (HND): 105
- Shanghai (PVG): 99
- London (LHR): 99
- Amsterdam (AMS): 87
- Paris (CDG): 78
- Vancouver (YVR): 62
- Taipei (TPE): 52
- Seoul (ICN): 40
Largest Markets Unserved by DL at SEA: Domestic
- Newark (EWR): 721
- Oakland (OAK): 623
- Houston (IAH): 599
- Burbank (BUR): 556
- Philadelphia (PHL): 389
Largest Markets Unserved by DL at SEA: International
- Toronto (YYZ): 206
- Frankfurt (FRA): 193
- Calgary (YYC): 154
- Dublin (DUB): 131
- Delhi (DEL): 130
The Present and Future of DL's Hub at SEA: what is and what is possible.
The data does suggest that DL’s primary purposes at SEA are O&D-based. It has a high O&D percentage, and the connections it takes come from a surprisingly non-diverse set of markets. For example, 17.3% of the domestic connections DL’s hub at SEA takes are from only one source: ANC. Many of the non-Alaska-based connections are to smaller cities in the Pacific Northwest, like GEG and PSC, or connections to Asia. But within each of these data points arises both opportunities and limitations for Delta.
First, the Limitations.
1) Competition with Alaska Airlines and Connectivity to/from Alaska
Seattle has very strong competition in the form of Alaska Airlines (AS) in the Seattle market. Alaska is based in Seattle and has a very strong hometown loyalty in the city. As of April 2025, AS has 51.9% of the market share to DL’s 24.3%. For comparison, in April of 2019, AS had 48.9% and DL had 23.5%. These numbers are based on onboards from a 12-month average. This tells us that, while DL is growing in SEA, so is its primary competition.
To build on the point above, it was surprising to see that ANC is the largest connecting market over SEA for DL. As mentioned, the connections provided by DL’s ANC-SEA by themselves are 17.3% of all the connections provided by DL at SEA domestically. Even with its lower cost of operation, AS receives a higher fare premium on SEA-ANC as well. On DL, 81.1% of their ANC-SEA route is connections. This is compared to 72.5% on AS. Because of this, I do not see the level DL relies on Alaska-based connections at SEA to be a positive thing. Connectivity to/from Alaska is a battle they will never win.
2) Lack of Connectivity and Gates
As of May 2025, 53.9% of traffic carried by DL on its flights between SEA and Asia is connections. That in itself isn’t a bad thing. 46.1% is a high O&D percentage for long-haul flying, but this also varies greatly by route. While SEA-PVG and SEA-HND are over 50% local, SEA-TPE is less than one-third local, and its loads are fairly low. SEA-ICN is operated by a joint venture between DL and Korean Airlines (KE), so it will naturally have large-scale connectivity. DL’s connectivity into SEA is fine for what it has, but if the goal is ever to expand beyond the destinations they offer, more connectivity will have to be provided to the SEA hub from a larger variety of destinations. However, with only priority access to 18 gates at SEA vs. the 47 exclusive gates that AS has access to, this is not as easy as it might seem. To feed flights to Asia, they would need more arrivals in the mid-morning hours, which is already a busy time for DL at SEA. Can they shoehorn in more flights? I don’t know that they can.
Now the Opportunities. 1) SEA as an O&D Destination
The Seattle market is both wealthy and growing. Between 2019 and 2025, the market has grown by around 2,800 PDEW, with the bulk of that being international. The market between SEA and East/Southeast Asia has grown by over 300 PDEW alone. The O&D between SEA and East/Southeast Asia also stimulates very well. For example, SEA-MNL grew by about 25% with the arrival of Philippine Airlines. DL is in a good position to continue to grow this market.
2) Delta's Product is Distinctly Unique from Alaska's
Delta has a very well-respected product offering. While I won’t go into the whole “which airline is better” back and forth, Delta One and Premium Select are both widely seen as premium and have great corporate appeal. Alaska’s long haul product is still a work in progress in many ways. We have yet to see how the corporate market in Seattle will react to it. Another small benefit DL has is in regards to their fleet. SEA-ICN/NRT will be flown on an Airbus A330-200 aircraft. While very capable and comfortable, they do have a higher cost of operation per seat as opposed to the 350-900 and the 330-300/900 aircraft that DL operates. While not huge, every little thing counts!
It's a Long Game where Delta has to do More with Less
I do not think Delta is expecting to win the war for SEA in any kind of short-term fashion; it will be a long game. For any airline that wishes to establish a dominant presence in a competitive market, it will require considerable aggression, and Delta has demonstrated its willingness to do so. But DL is in a situation where they have to choose their battles. They do not have the resources to compete with AS pound for pound in SEA due to the lack of gates DL has available compared to what AS has. They will not be able to offer the breadth of destinations AS does at SEA for this reason.
That said, DL has gotten the jump on AS in long-haul flying in SEA, and Delta is doing an excellent job of differentiating itself in the Seattle market. Delta’s on-board product is well respected and premium, with a wide appeal to the high fare and corporate markets. It appeals to and is sought after by American and foreign travelers alike. DL is building a Delta One Lounge in SEA, which will further differentiate them from their competitors.
Delta’s position in SEA is, quite frankly, unenviable. They will win many battles, but unless they can obtain more gates, it’s hard to see how they will win the war for Seattle. One might think of it similarly to American and United in Chicago, but I do not. The difference in product and the way DL has differentiated itself from AS has kept DL competitive in Seattle, and that is to their credit.
So, is SEA a Money Pit for Delta?
If you follow airline-based publications or visit airline-based forums, you have no doubt seen this rumor. Let me start off by saying that nobody outside a handful of people in Atlanta and perhaps Seattle knows the answer to that.
That being said, is SEA the poorest performing hub for Delta? We can look at the data available to us and get some clues. Here is what we know:
- Domestic fares are public, which allows us to calculate yields. While we cannot determine the international yields across Delta’s network, it is a true statement that SEA has the lowest domestic yields of any hub in Delta’s network. Domestically, DL’s yield at SEA is calculated at about .13. By comparison, ATL, DTW, MSP, and SLC are all above .20. Even more competitive hubs like BOS, LAX, and JFK are above .15. There is honestly no sugar coating it: a .13 domestic yield is quite low for an airline hub.
- DL is competing against AS, a carrier with a low cost of operation. That means that if DL is going to have to match fares to lure business, they will be matching fares that may be profitable for AS but not for them. This is not entirely unlike the battles Delta fights at LAX, BOS, or NYC, but SEA is a smaller market than those markets, especially for international demand. BOS is the closest to SEA in international demand, and it is a 12,638 PDEW to SEA’s 7,320.
- SEA’s geographic location will hamper domestic yields in general because the average stage length of its flights will be longer than a hub in a more central location. It is always important to remember: distance is the enemy of yield, and higher revenues and fares are needed to overcome the gap.
Based on the data and what we’ve covered, there is a strong possibility that SEA is probably DL’s worst-performing hub, but that does not mean that SEA loses money.
We cannot know whether or not SEA makes money or loses it for DL, but we do know that it is a very important hub for them. No airline is going to toss that amount of resources at a station if it were not something they valued. For that reason, I do not think DL is going to slow down or back off of their hub in Seattle. They are committed and in it for the long haul. Whether or not the hub makes money or not seems secondary to the importance DL places on it.
flyinghoustonian
September 16, 2025Still waiting on the supposed DL SEA-PHL and SEA-IAH adds, but it seems DL is concerned about going up against the competition on routes like those. Great article as always; very informative!
Amol Sharma
September 16, 2025Very interesting writeup as usual- out of curiosity, what is AS’s yields at SEA – similar to 0.13? If so I would think they might be leveraging their lower cost-basis at SEA vs DL, but long-term if they grow long-haul that could be tricky. Now if it is much higher then that’s a different argument.
Similarly on the PHX writeup you noted that while WN led AA in O&D traffic, in H2H comparisons on fares AA averaged ~$220 vs WN’s ~$150 on the same route. Any such corresponding figures for AS and DL?
Branson Heinz
September 17, 2025It’s honestly hard to compare them apples to apples. AS’s costs are just so different.
When DL and AS are compared, DL will have the fare premium advantage over as many if not most routes, but the problem is that we don’t know costs but its a pretty safe assumption that AS’s are much lower. So a .13 is not great for DL but for AS it might be just fine.
Branson Heinz
September 17, 2025PS. I was banned from that other site. So hit me up on here if you need. 🙂