Vasari players can't spam scouts to counter LF. Advent and TEC ones can, but Vasari can't (not effective in terms of cost, unfortunately)
And btw, this multi fleet, Carriers + LRFs are best things you can have and there is little counter to it. You notice that This combination basically counter EVERYTHING. Only thing can effectively counter this is BIGGER Carrier + LRFs or go for Heavy cruisers if he does not have enough bombers. You can go pure fighter carriers, but you will find out they are lackluster to anything other than LRFs and fighters (well, not really if you have a lot of them.)
You can put some flavor by putting some repair vessels, support ones but you must have MOAR carriers and LRFs to counter the combination.
According to armour and attack kinds of frigates and cruiers, the counter to Carriers + LRFs should be Light frigates + Flaks.
Oh well, Suppose FLaks would kill strikecrafts while dealing some heavy damages to LRFs, Light Frigates then chase carriers to kill them off.
This does not work because Light Frigates have too few HP, too expensive and Flaks are completely useless other than surpressing strikecrafts.
This is more of balance problem, and solutions are incredibly easy.
Change flak frigate's attack type to light (get rid of that silly very light anyway)
Buff light type attack against very light: 100% to 150%.
Slightly increase HP and shields of light frigates (or cost reduction)
Done. It should be tested and maybe some number adjustment needed.
Only side effects are fighters killing each other more faster (so faster game progress!) and a bit slower in colonization (being neutral frigates being tougher)
Now, because base damage is reduced, flak won't do much about anything else, but it will kill off LRFs so hard that it will Advent players cry (well, those like to spam illums.)
It also will 'surpress' fighters and bombers like current state, so light frigates can close and kill of carriers off, if they didn't die to LRFs...
So, let's see completed food chain.
Carriers > LRFs (fighters can kill off LRFs quickly thanks to 200% damage)
Light frigates > carriers (due to lack of medium damage from fighters/bombers, and LF does 150% to carriers)
Light frigates > flaks (again, 150% to flaks, and cheaper)
LRFs > Light frigates (due to incredible base damage, and 150% damage to medium, while LF only does 75% to LRFs)
Flaks > LRFs (200% damage, while LRFs do 75% to flaks)
Flaks >/= Carriers (they surely surpress strikecrafts in general. But not able to kill carriers themselves)
With this, no unit has definitive advantages, slightly favor to light frigates and flaks.
With this we can FINALLY see the mixed army of light, long-range, flak and carriers til mid game.
There would be other solutions, but it seems this is the one bring the least changes in values, yet proper affects on current games.