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If you can think of a third aspect, I would include it. I would not add to existing answers I thought were complete, unless I can bring in another aspect to them. Plus, your instinct to not have ...
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#4: Attribution notice removed
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#3: Attribution notice added
Source: https://writers.stackexchange.com/a/35861 License name: CC BY-SA 3.0 License URL: https://creativecommons.org/licenses/by-sa/3.0/
#2: Initial revision
If you can think of a third aspect, I would include it. I would not add to existing answers I thought were complete, unless I can bring in another aspect to them. Plus, your instinct to not have only two challenges is probably correct, surely there are more than two challenges / opportunities in almost any industry. On the challenge side, regulatory issues with noise pollution, suitable airfields, or concerning carbon footprints. Perhaps commercial challenges as well; with demand, or monopoly (of manufacturer or buyer; eg. only a few governments will buy.) There are opportunities as well, Mechanical with new engineered materials, new simulation technologies are arising, perhaps new markets are emerging. I think it would be better to keep your existing writing concise and add another topic, whatever other challenge/opportunity you find most compelling.