The Q2 earnings season is in full swing with a deluge of companies reporting their financial numbers each day. The picture to have emerged so far is a rosy one with many companies reporting better-than-expected earnings per share. Moreover, the growth rate with respect to the bottom line is also a healthy one.In fact, this healthy picture is unlikely to fade, with our latest Earnings Trends report suggesting that stocks in the much sought-after S&P 500 Index will end the current reporting cycle with bottom-line expansion of 8.6%. The same set of companies is projected to witness top-line growth to the tune of 4.7%.Notably, 11 of the 16 Zacks sectors are expected to end Q2 in the green as far as bottom line expansion is concerned. One such sector is the highly diversified Transportation sector. The participants from this space are likely to end this quarter with the top and the bottom line expanding 9.6% and 6.9%, respectively. Both these figures compare favorably with the readings in Q1, when revenues grew 6.9% and earnings contracted 17.8%.Significantly, multiple tailwinds like an improved economy, a better job market scenario and better unit revenue trends have contributed to this bullish picture for the sector. Already, this space has seen strong Q2 earnings reports from key players like Union Pacific Corporation UNP, JetBlue Airways JBLU and Kansas City Southern KSU that have outperformed on both the fronts.Given this backdrop, investors interested in the Transportation sector eagerly await the Q2 earnings releases by major sector participants like Southwest Airlines (LUV), United Parcel Service UPS, Old Dominion Freight Line, Inc. ODFL and Spirit Airlines SAVE on Jul 27.According to our quantitative model, a company needs the right combination of two key ingredients – a positive Earnings ESP and a Zacks Rank #3 (Hold) or better – to increase the odds of an earnings surprise. You can uncover the best stocks to buy or sell before they’re reported with our Earnings ESP Filter.Dallas-based, Southwest Airlines is a low-cost carrier, which have lesser chances of beating the Zacks Consensus Estimate in this quarter despite its Zacks Rank #2 (Buy). This is because it has an Earnings ESP of -1.67% as the Most Accurate estimate of $1.18 per share is pegged at 2 cents below the Zacks Consensus Estimate.Our model did not predict an earnings beat earlier as well. When we issued its Q2 earnings preview article, the company carried a Zacks Rank #1 (Strong Buy) while the Earnings ESP remained the same. You can see the complete list of today’s Zacks #1 Rank stocks here.Southwest Airlines Company Price and EPS Surprise Southwest Airlines Company Price and EPS Surprise | Southwest Airlines Company QuoteThe next company is United Parcel Service, the world's largest express carrier and package delivery company. It provides specialized transportation and logistics services in the United States and internationally. The chances of the company beating the Zacks Consensus Estimate for earnings in this quarter are also less. This is because it has an Earnings ESP of -0.69% as the Most Accurate estimate is $1.45, while the Zacks Consensus Estimate is pegged at $1.46. Moreover, it has a Zacks Rank #4 (Sell) (read more: Will High Costs Mar United Parcel's Q2 Earnings?).United Parcel Service, Inc. Price and EPS Surprise United Parcel Service, Inc. Price and EPS Surprise | United Parcel Service, Inc. QuoteOld Dominion Freight Line, a less-than-truckload multi-regional motor carrier, providing direct service throughout the United States. We expect the company to report better-than-expected earnings per share in this quarter. This is because it has an Earnings ESP of +0.92% as the Most Accurate estimate is at $1.10, while the Zacks Consensus Estimate is pegged at a penny lower. Also, the company currently holds a Zacks Rank #2.Old Dominion Freight Line, Inc. Price and EPS Surprise Old Dominion Freight Line, Inc. Price and EPS Surprise | Old Dominion Freight Line, Inc. QuoteFinally, Spirit Airlines is a low-cost passenger carrier based in Miramar, FL. The chances of the company beating the Zacks Consensus Estimate for earnings in this quarter are less, despite its Zacks Rank #3. This is because it has an Earnings ESP of -0.90% as the Most Accurate estimate of $1.10 per share is pegged at a penny below the Zacks Consensus Estimate (read more: What to Expect from Spirit Airlines in Q2 Earnings?).Spirit Airlines, Inc. Price and EPS Surprise Spirit Airlines, Inc. Price and EPS Surprise | Spirit Airlines, Inc. Quote The Hottest Tech Mega-Trend of AllLast year, it generated $8 billion in global revenues. By 2020, it's predicted to blast through the roof to $47 billion. Famed investor Mark Cuban says it will produce "the world's first trillionaires," but that should still leave plenty of money for regular investors who make the right trades early. See Zacks' 3 Best Stocks to Play This Trend >> 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 JetBlue Airways Corporation (JBLU): Free Stock Analysis Report Spirit Airlines, Inc. (SAVE): Free Stock Analysis Report Kansas City Southern (KSU): Free Stock Analysis Report Union Pacific Corporation (UNP): Free Stock Analysis Report Old Dominion Freight Line, Inc. (ODFL): Free Stock Analysis Report United Parcel Service, Inc. (UPS): Free Stock Analysis Report To read this article on Zacks.com click here.