Key PointsARK Space & Defense Innovation ETF has a higher expense ratio and higher historical volatility than First Trust Indxx Aerospace & Defense ETF.ARK Space & Defense Innovation ETF delivered a higher 1-year total return but has experienced a significantly deeper maximum drawdown.First Trust Indxx Aerospace & Defense ETF offers a more concentrated industrials focus and a passive index-tracking methodology.10 stocks we like better than Ark E…