A controller at Georgetown Municipal Airport (KGTU), after clearing N2889D, a Piper PA28-236 Dakota, to depart said, "What's your direction of flight, sir?", to which Stack replied, "Eight niner delta's going southbound, sir".
Georgetown airport is about 20 miles north of the crash site, a building that apparently contained Internal Revenue Service offices, an organization Stack was apparently unhappy with.
Later, when Stack had cleared the bounds of Georgetown's airspace, the controller called back and cleared Stack to change frequencies.
"See you later," the controller added.
"Thanks for your help," replied Stack. "Have a great day."
"You too," said the controller.