Micro is right: I am asking about carried fighters adding mass, not the hangars doing so.
Also I don't get the remark about fighters adding to buildpoints. That is just not true. ships or DPCs with hangar space are not built with a full complement of fighters.
example:
I have designed a small tender of 9000tons, the drive is capable of 9000tons as well, the ship has hangar space for 2000 tons of fighters.
We assign four fighters of 0.5kt, filling it to capacity.
Does the ship now weigh 11000 tons? Or does the game ignore the weight of carried stuff?
If it does weigh extra, I'd expect it to be slowed. Just like tugs are slowed by the extra mass they tow.
Also the jump engine might no longer work, depending on how and when JD validity is determined.
Playtesting my design is a bit un-handy right now, because I'm just finding out my pointdefence is worth buttkiss against my first enemy.