Buzzp,
Yes there is a great difference in price and performance in electronic components either passive or active between automotive and aerospace.
While automotive may accept and use standard parts aerospace mostly uses custom parts. Also most parts use for aerospace projects are de-rated; Voltage de-rating and temperature de-rating. The de-rating is a safety factor, e.g. a 2200 micro farad capacitor 16V, may be used by an automotive company as a standard part for 16v application, but an aerospace may have to de-rated it by .25, hence use it for a 12V application. There are also a lot of other factors that come to play, such as the number and kind of test verification that may be needed to validate the specific component
Regards, Geke