The transportation sector is highly diversified in nature including players such as airline companies, truckers, shipping companies and railroads. The sector has benefited immensely from the weakness in oil prices as the commodity forms one of the major inputs for such companies.With all the transportation companies in the S&P 500 index having already reported their financial numbers, the picture that has emerged is not too different from the one in the last few quarters. Cheap oil has acted as a boon, driving the sector’s bottom line in the current earnings season (+2.9%). Major players in the segment such as United Continental Holdings UAL and Southwest Airlines LUV posted an earnings beat, thanks to the extended slump in oil. Reflecting this, the percentage of transportation companies outperforming with respect to the bottom line is a healthy 85.7% (for the S&P 500 index) in Q1 earnings.However, as in the past few quarters, the top line is under considerable pressure this time too. In the Q1 earnings season, revenues have contracted 1.1% on a year-over-year basis with only 35.7% companies beating the Zacks Consensus Estimate for revenues.With the bulk of the transportation earnings reports already out, there are a few yet to disclose their quarterly numbers. Let’s take a look at transportation players – Air Transport Services Group, Inc. ATSG and GOL Linhas Aéreas Inteligentes S.A. GOL – scheduled to report first-quarter 2016 earnings this week.Air Transport Services Group, based in Wilmington, OH, is scheduled to release first-quarter 2016 results on May 10, after market close. The aircraft leasing company is not likely to outperform with respect to the bottom line, as per our quantitative model. This is because the company does not have the right combination of two key ingredients – positive Earnings ESP and a Zacks Rank #3 (Hold) or better – necessary for increasing the odds of an earnings surprise.Air Transport Services Group has an earnings ESP of 0.00% and Zacks Rank #3.Latin American carrier GOL Linhas, scheduled to report first-quarter results on May 11, has been struggling for quite some time due to a weak economy and foreign exchange headwinds. The Sao Paulo, Brazil-based carrier has been undergoing a thorough restructuring process to revive itself. Our model doesn’t predict that the carrier will outperform with respect to the bottom line in the first quarter.The Earnings ESP for GOL Linhas is 0.00% as the Most Accurate estimate is in line with the Zacks Consensus Estimate. The Zacks Rank #2 (Buy) of the company increases the predictive power of ESP but that alone does not guarantee a bottom-line beat. 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 >>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 AIR (LUV): Free Stock Analysis Report GOL LINHAS-ADR (GOL): Free Stock Analysis Report AIR TRANSPT SVC (ATSG): Free Stock Analysis Report UNITED CONT HLD (UAL): Free Stock Analysis Report To read this article on Zacks.com click here. Zacks Investment Research