Southwest would be one option as there are direct flights. However, United Airlines also has direct flights and gives the option of travelling in 1st class.
Frontier Airlines
No they don't fly there but they do go to Denver.
No, Southwest does not have any flights to and from Knoxville at all. However, United Airlines flies between Denver and Knoxville several times a week.
Yes Frontier airlines operates mainly out of Denver airport.
American Airlines, United Airlines, Aeromexico, Tam, Delta, Lan and Frontier Airlines. On AA is about 22 hours of flights.
At this moment in time (February 26th 2012) Southwest only flies into Denver, CO.
Frontier Airlines was bought by and is owned by Indigo Partners LLC. They have a fleet of 57 planes and are headquartered in Denver, Colorado.
It appears that Frontier Airlines offers the most arrival/departures to/from Denver/Los Angeles.
Only one airline flies into or out of Page, Arizona. Great Lakes Airlines offers flights to and from Los Angeles, Denver, and Phoenix.
People like to travel, but traveling is often expensive. If you're looking for a cheap flight from Los Angeles to Denver it's KAYAK and Expedia airline you're looking for. They offer 3x less than average cost.
Denver International Airport has 21 different airlines that fly in and out of it. Below I have included a list of all of them. Air Canada Airtran Airways Alaska Airlines American Airlines British Airways Champion Air Continental Airlines Delta Frontier Great Lakes Airlines Horizon Air jetBlue Airways Lufthansa Mesa Airlines Mexicana Midwest Airlines NWA Southwest Airlines Sun Country Airlines United US Airways
There are many airlines that fly from Oakland to Dallas. Some decent options include Southwest, Delta, and United. However, finding a direct flight is rare. Usually, there's a stop in Denver.