Wait, so if I don’t tell the brotherhood ,that starts the quest where I can bring the airship down
If you don't warn the BoS you become their enemy once this quest completed. The attack of the Prydwen is part of a Institute's main quest but if I remember correctly that happens later on
Why is your pipboy red. You’re a super demon.
You can change the color of your pipeboy in the settings on the main menu. It also changes the color of your lamp when you turn it on ;)