Southwest Airlines CEO: We used buybacks very appropriately

"I would certainly argue that buybacks need to be used very prudently. I think Southwest is a great example of where it worked," Southwest Airlines CEO Gary Kelly told CNBC Thursday. "When we did use buybacks, we used them appropriately. If you have high leverage and if you are impairing your ability to be able to grow or withstand a crisis, then obviously it's not the appropriate use."