Ultracapacitors for electric RC airplanes?

Just curious if any company or anyone is using ultracapacitors
(sometimes called supercapacitors) for RC aircraft.

I searched around and couldn't find anything.

A 350-farad (not a typo) ultracap is light and small. I don't think
they have quite the capacity of rechargeable batteries yet, but they
charge in seconds and weight almost nothing. 30 bucks or so each. I
figure something like this would be very useful for RC airplanes.

350 F cap - 2 ounces:
http://www.maxwell.com/ultracapacitors/products/BCAP0350.html

Regards

.