An expression of parting; a farewell as of to the enforcement of life-saving safety regulations or to one's family as one calls from an airplane the engine of which just popped off the wing because it hadn't been inspected since Pres. Oooh Look At My Aviation Safety Record left office.
Ex. "Welcome to the Transportation Department, Madame Secretary."
"Thank you so much. Do you happen to know when we had the last fatal commercial airline crash in this country?"
"It was the month after Obama took office. We've had a perfect record since then."
"Wow. Well, you can say chao to that shit. Now let's undo some regulations!"