This has been a "banner year" for urological meds; the pharmaceutical reps seem to be around with a new one every week. Seriously, though, there have been 3 or 4 new drugs introduced this year for overactive bladder that are competitors to detrol.

Having said that, if the person only has problems on airplanes, I would not prescribe an overactive bladder med. I'm sure your friend is aware of all of these ideas, but just in case:
---avoid caffeine
---avoid alcohol

These are both diuretics and will increase the amount of urination.

If he is on a diuretic (i.e. lasix) for medical reasons (usually blood pressure), he should see if he can take it after the flight.

Obviously it is difficult for me to diagnose someone based on a posting, and I am not a urologist, but these are a few suggestions.