Another cool thing to do would be mass electrolysis to produce hydrogen and then put it at every airport along the top 100 passenger routes. That’s all existing technology. Leave it to Boeing/Airbus to figure out how to put it in a plane. That would make a substantial cut in CO2 and give the potential for hydrogen cars and other inventions too (because you now have a big reservoirs of H2 in the top 50 world cities).
Eventually Apple would become the next Exxon-Mobil, which is normally quite profitable.