Start by making a copy of the fighter and/or bomber entity that you want, then do the same for the squad entity. Rename these new entities to fit your description. Add the new entities to the entity manifest for ENT and DIP. There is no manifests for vanilla which is why you need to include all the files in your the mod. Link the new fighter or bomber entity to the new squad entity.
GameInfo folder copies
FighterTechCombat.entity --> FighterTechSuicide.entity
SquadTechCombat.entity --> SquadTechSuicide.entity
FighterTechBomber.entity --> FighterTechHeavyBomber.entity
SquadTechBomber.entity --> SquadTechHeavyBomber.entity
entity.manifest
TXT
entityNameCount 1186 <--- add to count
entityName "FighterTechSuicide.entity"
entityName "SquadTechSuicide.entity"
entityName "FighterTechHeavyBomber.entity"
entityName "SquadTechHeavyBomber.entity"
Add the new squads to the ships, hangars and star bases you want. Here is the TEC hangars.
CAPITALSHIP_TECHBATTLESHIP.entity
CAPITALSHIP_TECHCARRIER.entity
CAPITALSHIP_TECHCOLONY.entity
CAPITALSHIP_TECHSIEGE.entity
CAPITALSHIP_TECHSUPPORT.entity
FrigateTechCarrier.entity
PLANETMODULE_TECHORBITALHANGARDEFENSE.entity
StarBaseTech.entity
squadTypeEntityDef:0 "SquadTechCombat"
squadAntiMatterCost:0 0.000000
squadTypeEntityDef:1 "SquadTechBomber"
squadAntiMatterCost:1 0.000000
squadTypeEntityDef:2 "SquadTechSuicide"
squadAntiMatterCost:2 0.000000
squadTypeEntityDef:3 "SquadTechHeavyBomber"
squadAntiMatterCost:3 0.000000
SquadTechSuicide.entity
fighterEntityDef "FighterTechSuicide"
SquadTechHeavyBomber.entity
fighterEntityDef "FighterTechHeavyBomber"
Once the copies are showing in game and tested wit the DEV.exes then start to modify the abilities, cost, hitpoints etc..
See http://soase.weebly.com/add-edit-ships.html by ZombiesRus
and http://soase.weebly.com/research-button.html which will also work for your icons, also by ZombiesRus.
The icons and string descriptions are all linked from the entity. Entity --> Brush ---> Icon and Entity--> String\English.str
I will look at the files again myself and post back a few details but that should get you started. What version is this for?