I went to a very interesting dinner yesterday evening with lots of presentations about future transport. There was much emphasis on battery electric vehicles and the use of the 5G systems to allow autonomous vehicles to operate efficiently in cities. Among the people I met there is still an acknowledgement that batteries are still too rare and expensive to really go the whole hog down the battery vehicle route, at least for now, and burning Methane and other light hydrocarbons is still hugely better than burning coal and heavier types.
More speculatively, electric air-liners are almost literally pie-in-the-sky, but there might be use of lighter jet engines for most of the flight with supplementary electric motors just for take-off and emergencies, as a sort of hybrid air-craft, reducing ground-level pollution somewhat.
There's a logic to saying that autonomous 'cars' should be drones so that people making short 'taxi-type' trips would be in the air rather than on the ground. This would free up the roads for more normal use, and get all those people who don't like driving out of the way up there. (Might be quite noisy -though.) The 5G system will allow the drones to safely negotiate the city airspace and not crash into each other too often.
The photo is taken from the website of EHANG, who are proposing passenger drones, among other remarkable things.