What: Shares of Spirit Airlines, (NASDAQ:SAVE) fell as much as 9.9% early Tuesday after the company reported June 2015 traffic and lowered its full-fiscal-year guidance.

So what: In a press release yesterday after the market close, Spirit announced traffic in June rose 25.1% year over year. That result was driven by a 28.5% increase in capacity (available seat miles), and held back by a 2.3 percentage point decrease in load factor to 87.1%. Spirit Airlines' preliminary systemwide completion factor for June was 95.3%.

Consequently in a separate SEC filing, Spirit also revealed "the domestic pricing environment softened further [from April], including for travel in the peak summer periods, due to competitor pricing actions." Now, Spirit Airlines anticipates fiscal 2015 operating margin of 21.5% to 23%, compared to its previous guidance provided in April of 24.5% to 26.5%.

Now what: It's encouraging to see Spirit's expansion continuing to progress well. But I also can't blame the market for taking a step back today given its weakness in the key summer season and subsequent guidance reduction. For now, and until this margin turbulence shows signs of abating, I'm content watching the stock from the sidelines. 

Steve Symington has no position in any stocks mentioned. The Motley Fool recommends Spirit Airlines. Try any of our Foolish newsletter services free for 30 days. We Fools may not all hold the same opinions, but we all believe that considering a diverse range of insights makes us better investors. The Motley Fool has a disclosure policy.