Air fighter (
Interceptor/
ASF) are pretty much the same for the most part (Cybran ASF are considered slightly weaker but have stealth).
Bombers/Gunships as well as T2 air is where the big differences are.
T1 Bomber: UEF/Cybran have spread out bombs which can miss/not kill stuff they should. Aeon has slightly less dmg compared to Sera but a stun ability.
Cybran also have a
T1 gunship which while not a good unit for a rush should not be underestimated.
On T2 air the
Aeon dominate with the swift wind, have a nice option for snipes with the mercy (but only when there is 0 AA around) and a Gunship that doesn't stand out a lot.
UEF has the Janus that has huge aoe on it's bomb and can wipe out a lot of t1 stuff and the Stinger which can carry units.
Seraphim has a t2FB that hits stationary targets reliably but has too little aoe to be any decent moving units and a regular gunship.
The
Cybran gunship has aoe and the T2 FB shoots missiles instead of bombs which hit moving targets really well which makes it a good acu-sniping tool.
On T3 you have a few differences between the
Strategic Bombers Cybran has the most aoe but the least dmg
UEF/Sera are somewhere in the middle
Aeon has the least aoe but deals the most dmg
All factions except for Sera have
T3 Gunships and while the Cybran/UEF T3 gunships are fairly similar the Aeon T3 gunship stands out because it can fight against air units to a certain degree as well as ground units.
In terms of Transports the rule of thumb is:
Cybran transports are the worst
UEF/Aeonare in the middle while UEF also has a T3 transport (other factions do not)
Sera has the best Transports in the same tech category