what airline has the cheapest tickets?

Cheapest tickets for what? Where? Dates? Seats? Region? Time?

There's a crap load of variables that determine ticket prices.

No airline will have the cheapest tickets all the time. I suggest you check out http://www.kayak.com.

The discount carriers will often have the cheapest tickets - Southwest, Jet Blue, Allegiant, Frontier, and Spirit. But not always. The ticket price depends on departure and destination cities (distance between them is really NOT a factor), and the dates of travel. The actual airline does not usually matter much.

You should use a site like kayak.com to compare fares for the tickets you want to find. You should also look at the discount carriers' sites, because those carriers are not usually represented on travel sites.

The airline that charges less for tickets. This is the aircraft category. I will move it, as you don't seem to grasp picking categories very well.

how do you get your teeth white just like having it done in the dentist office

Wright Brothers International Airlines, Inc. Bring goggles so you don't get bugs in your eyes, lol.

My experience has been Southwest.

In general, spirit and frontier for domestic flights but they have multiple fees for checked AND carry on bags as well as steep fees for changing dates. So you'll have to weigh all of the fees and in many cases, other airlines are still cheaper. But NO airline has the cheapest fares all the time. It always depends on dates and cities traveled

that varies day by day.

Southwest air because there are no baggage fees.