strobelite Nope, definitely not the Jetsons. Could've been a Hanna-Barbera cartoon with more realistic artstyle but on the whole I think it looked more along the lines of Thundercats, Captain Planet and other such things in terms of how it was drawn.
EDIT: I think I found it! Someone added a relevant entry to tvtropes about the one with artificial gills - seems to have been an animated Flash Gordon series, gotta check. Also I had a look on 1980s cartoon openings and kinda lost hope of finding the "opening starts from orbit" one since half of them seemed to fit the bill. XD
DeepSeaShark That's a long shot (since it's not really something I'd show to elementary school kids) but "Soul Music" based on Terry Prattchetts' book by the same name had a falling carriage and probably had ghosts as well (since one of the main characters is the anthropomorphization of Death). If not, then "Wyrd Sisters" (also based on a Terry Prattchett book, by the same animation company with the same style) definitely had ghosts though may have been lacking in the "falling carriages" department.