Depends if they want the window seat or not! lol I MUST have a window seat when flying or I go insane. No window seat is like going to Disneyland and staying in the car! So I like to travel alone for that reason. However its always good to have someone to share the experience with, and have someone to talk to, especially on long flights. As for in the airport, that's when I definitely want to be alone. My family always wants to go to the little museums, or gift shops and look around from now till eternity. I just quickly buy a key chain for my collection, and find the nearest and best window as fast as I can. I'll sit there watching planes, listening to the tower on my scanner till I have to make my way to my next flight.
My all time favorite person to travel with is my dad! He loves aviation just about as much as I do, and will always use the left ear piece when I listen to ATC. My father has been blind since he was about 25, so he has no use for the window seat, but he is constantly asking me what I can see, and I love describing it all to him. I'll sit there and tell him step-by-step what is going on. ie: "Flaps are going down... I can tell we are getting lower... ooh we have a vortex off the wing!... flaps are even lower... 3...2...1... touchdown." etc... etc... We have way too much flying!
Anyways back to the subject, as long as I'm traveling with my father, its all good. The rest of the family? Preferably not, but the times that's are not as pleasant, just make you enjoy the better ones all that much more.