Low-cost carrier Southwest Airlines Co. LUV posted a 6% rise in traffic (measured in Revenue Passenger Miles or RPMs) to around 12.4 billion in July from 11.7 billion a year ago. Also, Available Seat Miles (ASMs) increased 5.5% to 14.2 billion from 13.4 billion in the same month last year. Load factor (the percentage of seats filled by passengers) too improved 40 basis points (bps) to 87.3% in July as traffic growth outpaced capacity expansion.On a year-to-date basis, Southwest Airlines witnessed a 4.5% rise in RPMs to 76.1 billion. Also, ASMs rose 4.7% to 91.0 billion. Hence, the load factor decreased 10 bps to 83.6%. Additionally, passenger count in the first seven months of 2017 rose 4.5% to 91.7 billion from 87.7 billion during the same period in 2016.The company continues to expect third-quarter 2017 operating revenue per ASM (RASM) growth of around 1%.Southwest Airlines Company Price Southwest Airlines Company Price | Southwest Airlines Company QuoteThis Zacks Rank #3 (Hold) recently reported second-quarter 2017 financial numbers. The company reported better-than-expected earnings and revenues in the said quarter. The carrier’s earnings per share (on an adjusted basis) of $1.24 beat the Zacks Consensus Estimate of $1.20. Earnings also improved 4.20% on a year-over-year basis. Operating revenues of $5,744 million were marginally above the Zacks Consensus Estimate of $5733.2 million. Revenues too rose 6.69% year over year. You can see the complete list of today’s Zacks #1 Rank (Strong Buy) stocks here.Other airline heavyweights like American Airlines Group AAL, Spirit Airlines SAVE and Alaska Air Group ALK have also recently reported second-quarter 2017 earnings numbers. Both American Airlines and Alaska Air Group surpassed estimates in their results. However, Spirit Airlines reported better-than-expected earnings but lower-than-expected revenues in the quarter.One Simple Trading IdeaSince 1988, the Zacks system has more than doubled the S&P 500 with an average gain of +25% per year. With compounding, rebalancing, and exclusive of fees, it can turn thousands into millions of dollars.This proven stock-picking system is grounded on a single big idea that can be fortune shaping and life changing. You can apply it to your portfolio starting today.Learn more >>Want the latest recommendations from Zacks Investment Research? Today, you can download 7 Best Stocks for the Next 30 Days. Click to get this free report Southwest Airlines Company (LUV): Free Stock Analysis Report Spirit Airlines, Inc. (SAVE): Free Stock Analysis Report American Airlines Group, Inc. (AAL): Free Stock Analysis Report Alaska Air Group, Inc. (ALK): Free Stock Analysis Report To read this article on Zacks.com click here.