I will also add to the comments that aviation using hydrogen fuel cells or using hydrogen directly in turbine or piston engines is possible. However hydrogen is fraught with problems. It has a low volumetric energy density and if pressurized must be stored in relatively heavy high pressure tanks. It is relatively energy expensive to make especially if you are trying to be “green” and even more expensive if you try to liquefy it. It leaks thru everything and all you can do is slow down the rate of leakage. It also damages some materials. I think that there are better “more or less green” liquid fuels available including ethanol, isobutanol, synthetic kerosene type fuels, DME, etc. Maybe even ammonia (NH3).
I do think that battery powered planes will start to make small inroads. Off course, there are already a few self-launching sailplanes. The first will probably be basic trainers. Even if you are not worried about greenhouse gases, economics will drive this. I have seen a projected $23/hr all up cost compared to over $100/hr for a Cessna 172. I current drive a Chevy Bolt and also have a 3/4 ton crew cab long bed pickup. The Bolt costs less than 3 cents a mile to drive and has no scheduled maintenance and is just fun to drive. The pickup is north of 10 times the cost of the Bolt to drive. I do not know if Bye Aerospace or Eviation Alice will succeed in developing their commuter aircraft or not (personally, I would not invest my own money in them) but I do expect that it is coming. Again, it will be economics driving this as Bye was projecting a seat mile cost about 1/10 that of a Beechcraft King Air. It will probably take longer than projected and more than a few pioneers will end up with arrows in their backs or at least in bankruptcy court.
Is it theoretically possible to build long range battery powered aircraft to compete with a 787? Maybe. Lithium air batteries have a theoretical energy density close to gasoline. (40.1 MJ/kg for lithium-air compared to 46.8 MJ/kg for gasoline.) And the efficiency of the electric power train is much higher. However, I would not expect to see this for at least 2 decades and probably more.