I just got the 'Ready for takeoff' and I was curious if when you attack with a vehicle which is piloted, does the pilots' combat icons add to the vehicle or do they fall away?

They do not add to the vehicle. They grant some special abilities seen in parenthesis after their pilot cost and count as enhancements for units like Rogue Squadron X-Wing and Rouge 3

Also note that Pilot cards, when piloting, now turn into enhancements. They are no longer units.