Hi Ercikling,
An interesting topic. As you may appreciate, the matter of flying then diving is much less critical than that of diving then flying, hasn't really been studied, and simply needs to be approached with common sense & flexibility.
Here's what our very own scubadoc said about it in his Dive Medicine column in the Mar '00 edition of "Rodale's Scuba Diving" magazine:
"There are no guidelines concerning the time to dive after flying or having alcoholic beverages. However, mild dehydration can occur on long flights and alcohol consumption (and drinking caffeinated beverages) contributes significantly to dehydration. Dehydration is a definite risk factor in predisposing a diver to decompression illness because the washout of inert gas (nitrogen, in diving) is less effective in a dehydrated individual. There are few dive trips that don't start out with a complimentary rum punch (often provided by the dive operator), and one free drink often escalates into severalon top of what you might have had on the plane during the trip. There is a small uptake of nitrogen back to sea level partial pressure upon descent and exit from the aircraft. Residual nitrogen is referenced to nitrogen tissue levels above normal sea level values and a flight at 8,000 feet cabin altitude would result in lower tissue nitrogen levels than sea level. On descent, tissue nitrogen pressure would simply return to sea level amounts.
We should expect to see more decompression illness on the very first day of diving if there were a relationship between flying and drinking alcohol before diving. The Divers Alert Network (DAN) has reported some data suggestive of an increase in decompression accidents on the first day of diving of a trip. Their figures show that of the 88 cases reviewed from the Caribbean for 1994, 33or 37.5 percentoccurred on the first day. The remainder occurred on days two through seven. These numbers are far too small to establish a cause and effect, but are suggestive. It would certainly seem reasonable to wait at least 24 hours before diving, rehydrating yourself as much as possible and avoiding overkill with the alcohol."
I personally cannot bear to wait least 24 hours to dive, so I don't drink alcohol on the flight or before diving, start hydrating 2 days before I leave home & sleep on the plane.
Dive safely.
DocVikingo