FYI, and not that it matters, I think your current is off by a factor of 2/pi. There's no 2*pi in the current formula because the 60 Hz is the full frequency not the angular frequency. And there's an extra factor of 4 because in each full cycle sine wave there are four 220 kV steps: 0-220, 220-0, 0-(-220), (-200)-0.
(and all of this of course assumes that the metal helicopter has low enough resistance to charge up to the full voltage)
The current through a capacitor is I = ωC, where ω is in radians per second (ie, 2𝜋 60 Hz).
I think 220 kV is the RMS voltage, so you get RMS current from the formula above. Peak voltage would be √2 * 220 kV.
Indeed, both the capacitor and the arc are in series, so actual current and power is somewhat less. As the arc grows longer, there should be an optimum length where you get 1/√2 of the maximum power.
(and all of this of course assumes that the metal helicopter has low enough resistance to charge up to the full voltage)