A mate of mine was a US Army Air Traffic Control NCO in Vietnam who had several aircraft go down whilst he was working them. Stories of WWII lost aircraft and their crews being found always brings back his 'ghosts'. He says the one that haunts him the most was a flight of 4 AH1 Cobras (crew of 2 each) that radioed on the emergency frequencies that they were low fuel (~20 mins) and lost on top of a solid cloud layer over the Central Highlands. All attempts to contact them were futile and their last transmission was that they thought they were west of the Mang Yang Pass and were going to attempt to descend in the blind through the cloud layer in hopes of finding where they were. They were never heard from again and the SAR attempts came up empty.