Imagine buying a $900,000 plane with Garmin electronics that is obsolete in 5 years, but the plane is only certified with that electronics so you can't change it. I use 1940s "steam gauges" and an Ipad for nav. At least with your boat you can upgrade your electronics without suddenly being "unseaworthy". Oh, a Garmin electronic package upgrade will cost more than my plane is worth and the value of the plane doesn't go up with that upgrade. Only maintenance hog worse than boats is aircraft
