The grey "Free Fighter" tabs have (mostly?) pre-defined units (mostly Interceptors), so we shouldn't let the user decide which type of Fighter to use them for

[klauskopec]

The grey free fighter tabs have specific units that must be added into them. These are defined under the "Squadron Assigned" ability on the parental unit card.

The complete list is:
Kushan Mothership: 1 free fighter, an Interceptor
Kushan Carrier: 1 free fighter, an Interceptor
Taiidan Carrier: 1 free fighter, an Interceptor
Kadesh Fuel Pod: 2 free fighters, each is a Swarmer

The Taiidan "Imperial Flagship" has 1 free fighter tab, but no "Squadron Assigned" ability. Community assumption is that this is for space reasons and it's supposed to be 1 Interceptor (to be confirmed officially).

[klauskopec]

Also the free fighter should show cost 0 instead of its normal cost. I believe that's already considered in the "total cost" calculation, but not shown on the unit card.

[klauskopec]

This is related to #27