Flying or not I generally reckon two glasses of shampoo are about as much as I can manage before the novelty wears off.
I once went to a champagne tasting for sommeliers and wine merchants where more than 50 of the major champagne houses were represented and eveything was free.
Seeing as all the rest were professionals I was the only one swallowing and not spitting and let me tell you a Bollinger hangover is just the same as a
bog-standard cava hangover.