Come Fly With Me is so much more enjoyable when you realize you can just kill the ghouls. No, they're not immortal like in a Bethesda RPG altho you don't get quest XP for sending them into space or blowing up their rockets(honestly, 800XP is not worth the hassle) but if you're doing this for Manny, he won't care and he will let you progress the main quest forward. Protip: Tell them the Nightkin are cleared out and then let a few of them leave. Sometimes, the game will glitch and instead of teleporting, you will see them physically run to the basement, if so they will change into their Space Suits and let you get multiple copies, for selling or what have you. Problem is that this isn't consistent, once I got every single ghoul to travel directly and recently I only got 2-3 max, usually just one.