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: On Friday, airline holding company SkyWest (Nasdaq: SKYW) warned investors that its second-quarter earnings will probably be "lower than it previously anticipated." Higher crew costs, combined with mergers and acquisitions expenses from absorbing ExpressJet and losses at two of SkyWest's non-U.S. carriers, are going to deprive the company of its expected $0.25-per-share profit and limit SkyWest to breakeven results.

So what: SkyWest sent out a Friday press release, but that hasn't worked out so well for the company today. Shares are down 16% and still falling.

Now what: These shares cost investors nearly 10 times earnings before the warning -- a pretty rich valuation on a company that's only expected to grow 5% per year over the next five years. Now it seems SkyWest is going to fall short of even that growth goal. "Breakeven" results for Q2 should subtract $0.25 from this year's estimated $0.88 per share profit, and lift SkyWest to a sky-high valuation of nearly 17 times earnings.

If you thought SkyWest was a dog of a stock before the earnings warning, now you know that dog don't even hunt.

Can SkyWest catch a second wind? Add it to your watchlist and find out.

Fool contributor Rich Smith does not own (or short) SkyWest. The Motley Fool has a disclosure policy. Fools may not all hold the same opinions, but we all believe that considering a diverse range of insights makes us better investors.