I had a drink on a plane once. I was fifteen, but my countenance (and the broad-shouldered jacket I was wearing) made me look older, so when one of the servers asked me for what I wanted to drink, I answered, "Wine, please", and she promptly inquired upon whether I wanted a Chilean red or a French white.
I read the thread title in Snape's voice. Afterward, I tried to fill in the rest of what he might say.
"I am on my couch. Which of course is more reliable than Mr. Potter ever was, or his son."
"I am on my couch. You idiot. You think I'd be so undignified as to board a Muggle craft?"
"I will have to talk to the apothecaries responsible for brewing these sub-par intoxication potions."