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 Delta Air Lines (NYSE: DAL) soared more than 11%, and US Airways (NYSE: LCC) jumped 6% as both carriers joined Hawaiian Holdings (NYSE: HA) in reporting better than expected earnings.

So What: Delta and US Airways cited an improving market for leisure and business travel, reflected in higher revenues and load factors. "Load factor" is airline-speak for the percentage of available seats filled. During the quarter, Delta's fleet flew at 85.9% of capacity while US Airways' fleet flew at 84.4% of capacity. Both numbers were an improvement over last year's third quarter.

Now What: Airlines have made for awful investments over the past several years, but between lower fuel costs, capacity cuts, and employee givebacks, they're starting to look more like the sustainably profitable businesses they used to be. Even American Airlines parent AMR Corp. (NYSE: AMR) turned a Q3 profit, its first in three years.

Interested in more info on Delta Airlines and US Airways? Add Delta to your watchlist by clicking here. Add US Airways by clicking here.