Ah, like if we got rid of all methods that are over two hundred years old like non vertical farming and elected officials?
[youtube]https://www.youtube.com/watch?v=ME_rprRlmMM[/youtube]

We could use electrical magnetic engines instead of fossil fuels? 
[youtube]https://youtu.be/eBtxjyD01lo[/youtube]

Highspeed rail trains.
[youtube]https://www.youtube.com/watch?v=AyJEQjabJjI[/youtube]

For rp power ideas
Air benders can pop hot air balloons. Air benders should [i][u]only[/u][/i] have air craft of [i]any[/i] kind.

Air benders were way under powered! air bender should affect the O2 in the blood, stop people from breathing, seperate 02 to evaporate water, make water, snuff out fire, refract light with the atmosphere to create super powerful lasers, the list goes on....