this. They still sell a ton of 12v products to be used in vehicles with that type of plug. I don't see that plug completely disappearing soon.Those are different. I any semi new car only one of the outlets was capable of accepting the lighter. Now I don't think any of them. They are still 12V and shaped the same but the lighter won't work in them.
Carry-on? A good pair of binoculars, maybe with a tripod. Can see most of the Messier objects with them. Can see the Planets without details though.
This. A good Pelican or its knockoff case, with the foam insert that fits the scope.Just get a proper flight case for it and it would be fine.