Reading a little on the Decathlon history of airframe problems leaves one feeling a little uneasy ..
http://www.airbum.com/pireps/PirepCitabria.html
Despite being an aerobatic aircraft, this is a 1980 Decathlon, and a hired one at that. I wonder just what the history of this aircraft is? Accidents? Upgrades? .. Does this particular aircraft still wear wooden spars?? ..
Did the last pilot who rented, throw a show, and pull 6G's, and overstress the wings?? ..
After 4 full days, going on 5 .. and with 14 aircraft looking for him, including FLIR equipped aircraft .. you'd expect SOME result. They can find a wreck that happened 20 years ago? .. but not Fossett?
I fear the worst, and that a wing separated, and he speared in, leaving only a tiny footprint.
If it happened over a ravine, as is entirely possible, it may take 10 years to find the remains.
There are plenty of parallels, with wrecks not being found for years afterwards.
My personal opinion is that small aircraft, flying low and slow are more likely to have success, at finding wreckage, than anything else.
Despite high tech equipment, Eyeball Mk 1 is connected to Brain Mk 1, which has more computing ability than anything electronic .. and often a glimpse is all that's needed for Brain Mk 1, to say, "backtrack and just check that out".
Electronics will examine the narrow parameters that were inputted .. and if they don't fit, they move on .. possibly abandoning good clues.
The last possibility, is the one the search crews now seem to be thinking about seriously .. an underwater search. Despite there being little water out there .. there's always that million-to-one chance, that the plane went down, right over the only patch of water for miles.