United Sol never truly invested much into fighter crafts. They referred ship to ship combats to preserve resources. USF fighter craft (Codenamed Wasp) used ammunition and used batteries to power their engines. Using actual ammunition meant that United Sol wished to shy away from using fighter crafts.

In the history of United Sol, they had only one single model of fighter craft. The exterior design remained identical although its internals had seen numerous revisions.
United Sol Ark later passed an act to retire fighter crafts in year 9606. This act wasn’t complied entirely as only Earth defense fleet retired fighter crafts. All other fleets in Sol system still chose to employ fighter crafts.

USF fighter’s weapons, a fair of gatling guns, were too weak to inflict any sort of damage to cruisers. Even against a much smaller vessel, such as frigates, fighters had a hard time damaging its armor. However, against frigates which had its bridge exposed, fighters had a chance if they focused on bridge glass. Meanwhile, against cruisers, fighters had absolutely no chance. Even ramming into cruisers had little impact.

USF fighter, in fact any fighter crafts in general, provided little protection for its pilots. United Sol Ark used this as an excuse to retire fighters.