Really, space fighters are really a silly idea in the first place. The whole point of having fighters in today's military is force projection: you have a target over the horizon and planes are a good way to get your weapons over there with a minimal exposure of your humans' lives.
In space, there's no horizon! Your little ships are visible from beyond their own tactical range and get shot down before they do much good. They are too small to carry effective defenses. I'm sure the a small craft like a fighter would need hefty hardware to power a shield strong enough to protect against a full sized capitol ship's phasers or what-have-you. And to top it off, your sending real life people in these eggshells to get fried.
is a little different because fuel consumption never seems to be an issue, but if it were, you have to carry enough gas to get you to the fight and get you back
(assuming you like you pilots) which is double what you might need if you sent a drone out there.
It seems to me that the sole use of big ships on the line makes good tactical and strategic sense.
Of course, we do
see fighter-type craft in later years of Star Trek
, so what do I know...