Michale Birbeck wrote
Drinking has never made anyone do anything better
In fact alcohol is a banned drug in a number of sports because it improves performance. The effect is on fine muscle control and is of benefit in sports like rifle shooting and archery.
Larger quantities impair judgment and gross motor controls, but for small quantities i.e. a glass of wine or beer - you will be a more precise operator of any equipment requiring delicate manipulation. However, I guess this doesn't include most aircraft control functions...
On the same theme, caffeine is also a banned drug in many sports. It reduces reaction time at the expense of precision. Caffeine is banned in sports like fencing because of the advantage it gives. However caffeine doesn't seem to be useful for aircraft control - and may even be harmful.