I'm sorry, but I profoundly disagree with some of what's been posted here.
This pilot has not been jailed because he is an alcoholic but because he was a danger to the passengers who should have been able to trust him. A pilot who doesn't know where he is flying to hardly inspires confidence.
And if we assume there are other pilots who may be tempted to drink before flying - whether alcoholic or plain stupid - this sentence may make them think twice. If so, a serious accident may have been avoided.
Think of it the other way round. If you are tempted to drink and fly the knowledge that, if caught, you will get off with a counseling session is hardly a serious consideration. Losing your liberty most certainly is.