The mail went by boat, train and truck, it just goes faster by air, again a luxury. It goes even faster by email which requires no transportation. Airborne fire fighting is not essential, neither is medivac, they are just faster or different methods of delivery, as with medicines. Aviation aids globalisation so that time critical things can be made far away and transported, otherwise you just produce the product closer. Make smaller well positioned hospitals, train more specialists, so that patients need not be transported to centralised medical facilities and so on. Don't live in fire prone areas, which is still not a good idea as aerial application only makes the effort to stop wild fire slightly easier, no where near a panacea for it. That's how it all was before globalisation. Mass farmed goods and mined ores/gases on the other hand have to be transported. If we stopped aerial fire services and air ambulances, some, people will die. If you suddenly stop grain and rice shipments and gas, oil, coal, etc a lot of the world will starve or freeze, millions will die. If you stop aviation, we all get bored and cant eat fresh caviar anywhere we want. I mean you still could travel by ship or train, it would just take longer and foreign destinations would actually be foreign as the fresher local foods and things will go back to being exotic, not some warped looking version of what you have anyway.