I thought each empire only gets one, one of the big perks of federations is that they can have different FTL techs in their unified fleet.
There is a later jump drive tech which is basically the best of all worlds but it eventually causes some kind of ~big sci-fi galactic problems~
I thought they also said somewhere that you couldn't group ships with different kinds of FTL. That would seem to negate the federation advantage, and compel them to pick one for the unified fleet.
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