The old thread on this subject has expired and I was just looking up this info for holiday travel purposes and figured it might be helpful to others as well. Please post below if you have any additions or corrections.
You cannot bring bourbon aboard as a carry-on unless you bring it packaged in 3 oz. (or smaller) containers in a clear quart-size plastic ziploc bag. My understanding (although this is not certain) is that you could fill the ziploc bag with multiple 3 oz. containers filled with the same liquid, so if things turn desparate, you could prob get as much as 18 oz. (532ml) of bourbon on with you via carry-on.
For checked luggage, you can carry up to 5 Liters of alcohol, which would be six 750ml bottles and a 500ml or smaller bottle. I'm not sure how literally they interpret those regs though, and it's possible they only allow five full-size bottles regardless of whether they are 750ml or 1L.
Any bourbon over 140 proof (some bottlings of Stagg) cannot be placed in checked luggage. Note, however, that the high-proof prohibition does NOT apply to carrying the same 140+ proof liquid in 3 oz. containers in your carry-on...
Any alcoholic beverage less than 24% alcohol (beer and wine) is not subject to the 5L limit, so you could check a full case of wine in a wine shipper (as I am planning to do in a few weeks).
Traveling with Special Items: Alcoholic Beverages
Carrying Alcohol In Your Checked Baggage
Please note, you can’t take alcoholic beverages with more than 70% alcohol content (140 proof), including 95% grain alcohol and 150 proof rum, in your checked luggage.
You may take up to five liters of alcohol with alcohol content between 24% and 70% per person as checked luggage if it’s packaged in a sealable bottle or flask.
Alcoholic beverages with less than 24% alcohol content are not subject to hazardous materials regulations.
TSA Permitted & Prohibited Items: Food & Drinks