As jayraider notes, any fighters within 1" are immune to stealth - by virtue of being right on top of the damn thing.
This does not extend to other ships.
However - there is a special action availible to fighters; Scanners to Full!. This is essentially a short-range version of the Scout special ability, allowing them to (attempt to) weaken the stealth value of a target ship, leaving it much more open to be shot at.