Alaska Air Group ALK revised its guidance for the second quarter of 2021.Per a SEC filing, the airline now anticipates capacity, measured in available seat miles, to decline 21% in the second quarter of 2021 from the comparable period in 2019. Previously, the same was estimated to decrease approximately 20% from the 2019 level.Revenue passengers are estimated to be down 28% from the second quarter of 2019 compared with the previous expectation of a decline of around 28-30%. For the second quarter, passenger load factor (percentage of seats filled with passengers) is estimated to be 77%, better than the previous expectation of 74-76%.With improvement in passenger demand, Alaska Air now anticipates total revenues to drop 33% in the second quarter from the 2019 level compared with the previous forecast of a decline in the range of 33-35%.Cost per available seat mile, excluding fuel and special items, is estimated to increase 10% in the second quarter from the 2019 level compared with the previous expectation of a rise in the band of 12-14%. The airline attributed the improvement in projection to approximately $15 million “in favorable updates to benefits-related expenses.”Alaska Air improved the projection for second-quarter cash flow from operations to around $830 million from $650-$750 million anticipated previously. The company stated, “Second quarter operating cash flow results were better than expected as a result of strength in demand for future travel, improvements in affinity partner cash flows as consumer spend levels surpassed 2019, and other working capital tailwinds.”For the second quarter, economic fuel cost per gallon is projected to be $1.90, compared with the previous estimate of $1.91-$1.93. Second-quarter results will be available on Jul 22.On a separate note, Alaska Air recorded positive pretax margin in June, marking its “first adjusted profit since February 2020.”Shares of the company have gained 5% so far this year against the industry’s 1.8% decline, primarily on optimism surrounding the recovering air-travel demand.Image Source: Zacks Investment ResearchZacks Rank & Key PicksAlaska Air carries a Zacks Rank #3 (Hold). Some better-ranked stocks in the broader Transportation sector are Landstar System LSTR, Expeditors International of Washington EXPD and ArcBest Corporation ARCB. While ArcBest sports a Zacks Rank #1 (Strong Buy), Landstar and Expeditors carry a Zacks Rank #2 (Buy) each. You can see the complete list of today’s Zacks #1 Rank stocks here.Shares of Landstar, Expeditors and ArcBest have rallied more than 28%, 59% and 89% in a year’s time, respectively. 5 Stocks Set to Double Each was hand-picked by a Zacks expert as the #1 favorite stock to gain +100% or more in 2021. Each comes from a different sector and has unique qualities and catalysts that could fuel exceptional growth. Most of the stocks in this report are flying under Wall Street radar, which provides a great opportunity to get in on the ground floor. Today, See These 5 Potential Home Runs >>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 Expeditors International of Washington, Inc. (EXPD): Free Stock Analysis Report Alaska Air Group, Inc. (ALK): Free Stock Analysis Report ArcBest Corporation (ARCB): Free Stock Analysis Report Landstar System, Inc. (LSTR): Free Stock Analysis Report To read this article on Zacks.com click here. Zacks Investment Research