Hi,
I've flown numerous times without any problems after one of my eardrums burst as a result of an infection. Mydoctor assured me that I was very unlikely to experience problems and that seems to have been the case so far. In fact I went off on a longhaul holiday very soon after the drum burst and it didn't seem to have any effect on the actual healing process either. My GP told me very cheerfully that it was a good job it burst when it did - having been plagued with a series of ear infections he said that I'd have fewer problems now and especially if it was still slightly perforated by the time I flew!
The scar tissue issue can go both ways - in my case it would appear that the scar tissue is actually thicker than the original membrane - it's left me with some loss of hearing as a result but it's never been a problem flying since it happened.
SM