"Rodger That"

As someone with 9600 Flying hours (mostly in C-130s) I can explain Roger and Wilco.
When you say "Roger" on the radio, that means you heard what the other person said and you understood it. So technically, when you say "Roger that", you are saying "I understand that".
Wilco is short for "Will Comply" When you say it on the radio, you are saying that you understood the directions you were given and that you will comply with them. For example, If Los Angeles Approach Control says, "Herky 49, descend and maintain 10,000 feet" You might say, "Wilco, Herky 49 descending to 10,000 feet." We actually did not say Wilco very much. We would usually repeat the instructions and say something like, "Roger, Herky 49 descending to 10,000 feet." There you go.