[AmVess]

It's difficult even on land. I recall an accident that involved a twin engine light aircraft that vanished in the middle of the night in Alaska perhaps 20 years ago.

Search parties searched for quite some time, but gave up. Five years later, the plane was found in the woods some 100 meters away from a fairly frequently traveled two-lane road.

[alexeisadeski3]

Forget Alaska, there are crashes in Nevada which haven't been found after decades.

A large airliner would be easier to find on land though - just look for the glow.

[crazytony]

Aside from Alaska (which has some radar limitations due to the terrain) I'm pretty sure none of those accidents occurred after coast-to-coast radar coverage came in to force in the continental US.

Believe it or not until 1973! there were massive land-based lighthouses all across the United States that would illuminate the aerial pathways that aircraft would use to get across the United States.

http://en.wikipedia.org/wiki/Airway_beacon

[gonzo]

Steve Fossett died in 2007, flying just outside NV. http://en.wikipedia.org/wiki/Steve_Fossett#Death

[jccooper]

"By September 10, search crews had found eight previously uncharted crash sites,[54][55] some of which are decades old,[56] but none related to Fossett's disappearance."

Wow.

[crazytony]

He was found a year later not decades later.

To be clear though: I was talking commercial operations which generally operate above the radar plane. I'm not even sure how/if Fosset's plane would appear on radar as he had no ADS and he didn't file a flight plan which means he was in class G or possibly E airspace on a VFR mission (very low altitude).