Low-cost carrier Spirit Airlines SAVE is scheduled to release its first-quarter 2016 results, before the opening bell on Apr 26.The Miramar, FL-based discount carrier has an impressive track record with respect to earnings having outshined the Zacks Consensus Estimate in three of the last four quarters. The average earnings beat is 2.88%.Factors at PlayEarlier in the month, Spirit Airlines raised the operating margin guidance for the first quarter of 2016 to approximately 21.5% from the previous outlook of 19% to 20.5%.The company attributed the improved guidance to better-than-expected revenues that was driven by strong ticket revenues per passenger. Adjusted cost per available seat mile, excluding fuel, is projected to decline approximately 2 % (the previous guidance had estimated a decline of 2.5% to 3.5%). Capacity at Spirit Airlines is projected to grow 26.5% in the first quarter. The carrier expects its total revenue per available seat mile (TRASM) to decline approximately 14% on a year-over-year basis. The company also stated that its TRASM projection was better than expected, thanks to prudent revenue management.Moreover, results at Spirit Airlines, as with the other carriers, will be benefitted by low fuel costs. The company expects fuel to cost around $1.22 per gallon in the quarter, representing a significant decline from the year-ago figure.Recently, the company received encouraging news on the labor front when it inked a tentative five-year agreement with the union (Association of Flight Attendants) representing its flight attendants. However, ratification of the provisional deal is awaited. However, the competitive pricing environment presents a challenge for the low-cost carrier. We expect a commentary on the provisional deal and the pricing issue at the first-quarter conference call.Earnings WhispersOur proven model does not conclusively show that Spirit Airlines is likely to beat the Zacks Consensus Estimate this quarter. This is because a stock needs to have both a positive Earnings ESP and a Zacks Rank #1 (Strong Buy), 2 (Buy) or 3 (Hold) for this to happen. Unfortunately, this is not the case here as elaborated below.Zacks ESP: Spirit Airlines has an earnings ESP of 0.00%. This is because the Most Accurate estimate is in line with the Zacks Consensus Estimate of 97 cents.Zacks Rank: Spirit Airlines has a Zacks Rank #3. However, this alone is not sufficient to secure an earnings beat.Stocks to ConsiderHere are some transportation companies you may want to consider as our model shows these have the right combination of elements to post an earnings beat this quarter.Copa Holdings CPA, with an earnings ESP of +8.70% and a Zacks Rank #3. The company is scheduled to report first-quarter earnings on May 5.Allegiant Travel Company ALGT, with an earnings ESP of +0.47% and a Zacks Rank #3. The company is scheduled to report first-quarter results on Apr 27.SkyWest, Inc. SKYW, with an earnings ESP of +16.00% and a Zacks Rank #2. The company is scheduled to report first-quarter results on Apr 28. 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 COPA HLDGS SA-A (CPA): Free Stock Analysis Report SKYWEST INC (SKYW): Free Stock Analysis Report ALLEGIANT TRAVL (ALGT): Free Stock Analysis Report SPIRIT AIRLINES (SAVE): Free Stock Analysis Report To read this article on Zacks.com click here. Zacks Investment Research