With your numbers and a hanful of assumptions, we can conclude then that you can drink 2 pints of average beer and be safe to drive legally immediately and legally fit to fly after 2 hours. I think I might leave it a bit longer for both activities myself.
The difficult thing to judge is the morning after a few beers. Especially when you can't quite remember how many you drank or quite how you got home. 8 pints with chasers equates to an 18 hour recovery period!
