Electric planes will fly circles around gasoline planes in
the near future.

"In the drive to devise more efficient and durable batteries, one
promising option uses carbon nanotubes, which not only can store far
more electricity by weight than lithium ion batteries but also retain
their charge for a much longer time."

https://www.scientificamerican.com/a...charging-ahead
http://www.youtube.com/watch?v=P8Pb_psj1A8
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Mark