I believe (but don't want to hunt for the old thread
) that someone did an experiment by stacking 15+ jet fighters all in one city, all set to AS. The results very strongly suggested that only one jet aircraft gets its 50% chance at each bomber, but that therefore the combined force of jets will get the 50% chance at up to 15+ bombers. (i.e., one would expect a startingly high kill rate on the first bomber each turn if each of 15+ jets had a 50% chance to intercept that first bomber, and this didn't happen in the experiment).
Can't increase range over 8 in current editor. Could change with next patch? Don't know.
Catt