Sifting through countless of stocks in the Passenger Airlines industry can be tedious, and sometimes two stocks are just too similar to judge which is the better investment. If you’re on the fence about investing in Delta Air Lines, Inc. or Southwest Airlines Co. because you’re not sure how they measure up, it’s important to compare them on a few factors before making your decision.

Read on to learn how Delta Air Lines, Inc. and Southwest Airlines Co. compare based on key financial metrics to determine which better meets your investment needs.

About Delta Air Lines, Inc. and Southwest Airlines Co.

Delta Air Lines, Inc. provides scheduled air transportation for passengers and cargo in the United States and internationally. The company operates through two segments, Airline and Refinery. Its domestic network centered on core hubs in Atlanta, Detroit, Minneapolis-St. Paul, and Salt Lake City, as well as coastal hub positions in Boston, Los Angeles, New York-LaGuardia, New York-JFK, and Seattle; and international network centered on hubs and market presence in Amsterdam, Bogota, Lima, Mexico City, London-Heathrow, Paris-Charles de Gaulle, Santiago (Chile), Sao Paulo, Seoul-Incheon, and Tokyo. The company sells its tickets through various distribution channels, including delta.com and the Fly Delta app; and acts as a reservations specialists. It also provides aircraft maintenance and engineering support, repair, and overhaul services; and vacation packages to third-party consumers. The company operates through a fleet of approximately 1,292 aircraft. Delta Air Lines, Inc. was founded in 1924 and is headquartered in Atlanta, Georgia.

Southwest Airlines Co. operates as a passenger airline company that provides scheduled air transportation services in the United States and near-international markets. As of December 31, 2024, the company operated a total fleet of 803 Boeing 737 aircraft; and served 117 destinations in 42 states, the District of Columbia, and the Commonwealth of Puerto Rico, as well as ten near-international countries, including Mexico, Jamaica, the Bahamas, Aruba, the Dominican Republic, Costa Rica, Belize, Cuba, the Cayman Islands, and Turks and Caicos. It also provides inflight entertainment and connectivity services; and Rapid Rewards loyalty program that enables program members to earn points for dollars spent on Southwest base fares. In addition, the company offers a suite of digital platforms to support customers' travel needs, including websites and apps; and SWABIZ, an online booking tool. Further, it provides ancillary services, such as Southwest's EarlyBird Check-In, upgraded boarding, and transportation of pets and unaccompanied minors. Southwest Airlines Co. was incorporated in 1967 and is headquartered in Dallas, Texas.

Latest Passenger Airlines and Delta Air Lines, Inc., Southwest Airlines Co. Stock News

As of December 12, 2025, Delta Air Lines, Inc. had a $45.3 billion market capitalization, compared to the Passenger Airlines median of $5.0 million. Delta Air Lines, Inc.’s stock is up 15.4% in 2025, up 4% in the previous five trading days and up 11.22% in the past year.

Currently, Delta Air Lines, Inc.’s price-earnings ratio is 9.8. Delta Air Lines, Inc.’s trailing 12-month revenue is $62.9 billion with a 7.4% net profit margin. Year-over-year quarterly sales growth most recently was 6.4%. Analysts expect adjusted earnings to reach $5.896 per share for the current fiscal year. Delta Air Lines, Inc. currently has a 1.1% dividend yield.

As of December 12, 2025, Southwest Airlines Co. had a $21.3 billion market cap, putting it in the 87th percentile of all stocks. Southwest Airlines Co.’s stock is up 22.5% in 2025, up 8.8% in the previous five trading days and up 23.12% in the past year.

Currently, Southwest Airlines Co.’s price-earnings ratio is 61.9. Southwest Airlines Co.’s trailing 12-month revenue is $27.6 billion with a 1.4% net profit margin. Year-over-year quarterly sales growth most recently was 1.1%. Analysts expect adjusted earnings to reach $0.996 per share for the current fiscal year. Southwest Airlines Co. currently has a 1.7% dividend yield.

How We Compare Delta Air Lines, Inc. and Southwest Airlines Co. Stock Grades

Stock evaluation requires access to huge amounts of data and the knowledge and time to sift through it all, make sense of financial ratios, read income statements and analyze recent stock movements. AAII created A+ Investor, a robust data suite that condenses data research in an actionable and customizable way suitable for investors of all knowledge levels, to help investors streamline and work through such data.

AAII’s proprietary stock grades come with A+ Investor. These offer intuitive A‐F grades for each of five key investing factors: value, growth, momentum, earnings estimate revisions and quality. Here, we’ll take a closer look at Delta Air Lines, Inc. and Southwest Airlines Co.’s stock grades to see how they measure up against one another.

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Delta Air Lines, Inc. and Southwest Airlines Co. Stock Value Grades

Company	Ticker	Value
Delta Air Lines, Inc.	DAL	B
Southwest Airlines Co.	LUV	B

Successful stock investing involves buying low and selling high, so stock valuation is an important consideration for stock selection.

Buying stocks that are going to go up typically means buying stocks that are undervalued in the first place, although momentum investors may argue that point.

AAII’s A+ Investor Value Grade derives from a stock’s value score. The Value Score is the percentile rank of the average of the percentile ranks of the price-to-sales ratio, price-earnings ratio, enterprise-value-to-EBITDA (EV/EBITDA) ratio, shareholder yield, price-to-book-value ratio and price-to-free-cash-flow ratio. The score is variable, meaning it can consider all six ratios or, should any of the six ratios not be valid, the remaining ratios that are valid. To be assigned a Value Score, stocks must have a valid (non-null) ratio and corresponding ranking for at least two of the six valuation ratios.

Stocks with a Value Score from 81 to 100 are considered deep value, those with a score between 61 and 80 are a good value and so on.

Delta Air Lines, Inc. has a Value Score of 76, which is Value. Southwest Airlines Co. has a Value Score of 61, which is Value.

The Value Stock Winner: It’s a Tie!

Looking at the Value Grade breakdown above, both Delta Air Lines, Inc. and Southwest Airlines Co. have a Value Grade of B. For investors who focus solely on a company’s valuation, you will need to conduct further research into both of these companies’ other metrics to see if they could be good additions to your portfolio. It’s important for investors to analyze multiple factors based on a wide range of metrics before deciding whether to buy.

Delta Air Lines, Inc. and Southwest Airlines Co.’s Quality Grades

Company	Ticker	Quality
Delta Air Lines, Inc.	DAL	B
Southwest Airlines Co.	LUV	B

Like the Value Grade, AAII’s A+ Investor Quality Grade comes from the percentile rank of key metrics. Specifically, the Quality Score is the percentile rank of the average of the percentile ranks of return on assets (ROA), return on invested capital (ROIC), gross profit relative to assets, buyback yield, change in total liabilities to assets, accruals, Z double prime bankruptcy risk (Z) score and the F-Score.

The score is variable, meaning it can consider all eight measures or, should any of the eight measures not be valid, the remaining measures that are valid. To be assigned a Quality Score, stocks must have a valid (non-null) measure and corresponding ranking for at least four of the eight quality measures.

The Quality Score is used to assess the underlying “quality” of a particular stock. A higher-quality stock possesses traits associated with upside potential and reduced downside risk. Backtesting of the Quality Grade shows that stocks with higher grades, on average, outperformed stocks with lower grades over the period of 1998 through 2019.

Stocks receive better grades (higher scores) for having higher scores for the quality subcomponents and worse grades (lower scores) for lower scores for the subcomponents.

Delta Air Lines, Inc. has a Quality Score of 67, which is Strong. Southwest Airlines Co. has a Quality Score of 79, which is Strong.

The Quality Grade Winner: It’s a Tie!

Looking at the Quality Grade breakdown above, both Delta Air Lines, Inc. and Southwest Airlines Co. have a grade of B. For investors who focus solely on a company’s overall quality, you will need to conduct further research into both companies to see if they are a good fit for your portfolio. As a good rule of thumb, you should always analyze multiple factors based on a wide range of metrics before choosing a company to invest in.

Delta Air Lines, Inc. and Southwest Airlines Co.’s Momentum Grades

Company	Ticker	Momentum
Delta Air Lines, Inc.	DAL	B
Southwest Airlines Co.	LUV	B

Momentum grades help to uncover stocks experiencing anomalously high rates of return; research finds that stocks with high relative levels of momentum tend to outperform, whereas those with low levels of momentum tend to continue underperforming. Momentum is based on the price change of a stock over a specified period relative to all other stocks.

Typically, AAII looks at the weighted relative strength over the trailing four quarters. The weighted four-quarter relative strength rank is the relative price change for each of the past four quarters. The most recent quarterly price change is given a weight of 40% and each of the three previous quarters are given a weighting of 20%.

Delta Air Lines, Inc. has a Momentum Score of 68, which is Strong. Southwest Airlines Co. has a Momentum Score of 78, which is Strong.

The Momentum Grade Winner: It’s a Tie!

Looking at the Momentum Grade breakdown above, both Delta Air Lines, Inc. and Southwest Airlines Co. have a grade of B. For those who focus solely on a company’s momentum, further research will need to be conducted into both companies to see if they fit your individual needs as an investor.

Other Delta Air Lines, Inc. and Southwest Airlines Co. Grades

In addition to Value, Quality and Momentum, A+ Investor also provides grades for Growth and Estimate Revisions.

Earnings estimate revisions scores take into account the magnitude of a company’s earnings surprise in its last two reported fiscal quarters. Often, surprises beget further surprises‐or at least continued sales growth (the exact opposite is generally true, too).

Growth investing builds on the idea that stocks of companies exhibiting strong, consistent and prolonged growth outperform those of slower-growth companies. AAII measures growth through consistency of annual sales growth, five-year sales growth rankings adjusted for extreme levels, and consistency of positive annual cash from operations.

These 2 key factors, when combined with the above, provide a holistic view into a particular stock. Further, by joining A+ Investor you can see whether Delta Air Lines, Inc. and Southwest Airlines Co. pass any of our 60+ stock screens that have outperformed the market since their creation.

So, Which Is the Better Investment, Delta Air Lines, Inc. or Southwest Airlines Co. Stock?

Overall, Delta Air Lines, Inc. stock has a Value Score of 76, Momentum Score of 68 and Quality Score of 67.

Southwest Airlines Co. stock has a Value Score of 61, Momentum Score of 78 and Quality Score of 79.

Comparing Delta Air Lines, Inc. and Southwest Airlines Co.’s grades, scores and metrics can act as a solid basis to determine whether they may be a good investment or not. You’ll also want to look at your portfolio’s asset allocation as well as your risk tolerance and financial goals to see if either of these stocks would make a good fit for you. AAII can help you figure out which investments align with your individual needs and preferences.

Investors are encouraged to do their own due diligence and research. In this way, individuals can effectively become managers of their own assets‐without having to rely on others for financial independence. You can count on AAII for timeless articles on financial planning and stock-picking, unbiased research and actionable analysis.

A+ Investor adds to our qualitative teaching with a powerful data suite to help you whittle down investment choices to find stocks, exchange-traded funds (ETFs) or mutual funds that meet your needs.

AAII Disclaimer

We make no representations or warranties that any investor will, or is likely to, achieve profits similar to those shown, because past, hypothetical or simulated performance is not necessarily indicative of future results. Before making an investment decision, you should consider your circumstances and whether the information on our content is applicable to your situation. This information was prepared in good faith, and we accept no liability for any errors or omissions. The full disclaimer can be read here.