What is the best combination of credit card and airline to get the most free/discounted (Miles)flights?
Will be needing to fly from California to Tennessee often - just trying to see what I can do to make that the most cost efficient as possible.
-Thanks
How many miles does it usually take for a flight?
Miles offered by the credit card companies work for any airline (not creditcards specific to an airline - Know they would be just for that one - but the others) ???

Most credit cards should have travel reward plans. Here’s a website that you can compare and choose from. Good luck.
There are several good credit cards that can earn miles/points that are good toward tickets on any airline, don’t have blackout dates, etc.. For example, the AmEx Blue Sky card is basically at 1.33% rewards card on all your spending. The Capital One No Hassle Miles Ultra for Professionals is a nearly 2% rewards card if you apply the earnings toward airline tickets.
There are many such good rewards cards. You can use this rewards calculator to see which one will pay you the most for your normal spending profile: