Scotts Cheap Flights - You can save thousands on out-of-country flights if you are willing to book right away! Please see THIS POST for more details on this!
Allegiant If you are flexible on when and where they will save you hundreds!
Frontier KIDS FLY FREE - yup, you're reading right! After a one-time charge of $50 dollars, your kids can fly for free, up to 12 years old.
Southwest - Build up airline miles and you can get flights for cheap or sometimes free! More to come!