Here are all the Aeolus cruisers in FreeSpace:
Single:
GTC Adamant
GTC Vigilant
GTC Warwick
GTC Agrippa
GTC Stalwart
GTC Templar
GTC Malta
GTC Ertanax
GTC Sparta
NTC Camisard
NTC Liberty
NTC Epigoni
NTC Loyola
NTC Mylae
NTC Hellespont
NTC Saharan
Multi:
GTC Ascendant*
GTC Ashaton*
GTC Zanthar*
GTC Alpha*
GTC Zeta*
NTC Retribution
NTC Righteous
NTC Vindication
NTC Vengeance
The ones with an asterisk are "simulated".
These are all the confirmed ships. It's implied that there are other Aeoluses but we don't see them in-game. So, depending on your counting strategy, there are 16 (single-player only), 20 (single plus multi), or 25 (single plus multi plus simulated) distinct Aeoluses. So I find it very hard to believe there are only 24 total, especially since the first production run ended before the NTF insurgency even began.