Although we don't believe in timing the market or panicking over market movements, we do like to keep an eye on big changes -- just in case they're material to our investing thesis.

What: Shares of Allegiant Travel Company (NASDAQ:ALGT) fell as much as 18.5% today after reporting earnings.

So what: Fourth-quarter revenue rose 7%, to $238.5 million, and net income was up $17.5 million, or $0.94 per share, $0.01 ahead of estimates. But management expects costs per seat mile, excluding fuel, will rise 4%-7% in 2014, and 13%-15% in the first quarter alone, which will sap profitability. 

Now what: Training A320 crews has been delayed because of the FAA shutdown, which alone is more than half of the expected cost increase next year. Revenue is also expected to be negative in the first quarter, so there are not a lot of positives to point to. There are too many headwinds and not enough value for me to buy in today, and I'll need to see solid revenue growth and cost reductions in the second half of the year to get excited about Allegiant.