From the old joke:
Stewardess: "Would you like some TWA Orange Juice, or some TWA Coffee?"
Passenger: "No thanks. But could I wouldn't mind some of your TWA Tea."
A Twat - a generally stupid or useless person, e.g. who will never get past the second round at Wimbledon despite the alcoholic chantings of work-shy sadsters on a soggy hill.
That Tim Henman is a bit of an airline beverage.