I am curious as to why nobody mentions mobile radio's as a possibility? I am to young to know the state of PMR in the early 70's but young enough and from a background where hand-helds had good range 2-3miles on the ground and small enough to be highly portable (pre-mobile phone days).
A big speculative "if" but could he have co-ordinated a drop with someone on the ground using radio? range is hugely extended with height and a 20 mile "line of sight" is possible with a plane at altitude. Potential scenario is that IF he/they knew the flight path someone could "spot" for him even without a visual cue through the noise of the plane passing overhead?
CB walkie talkies were widely available in 1971 and had RF power ranges of 0.1 to 5 watts in the 27 MHz band. Range HUGELY depended on terrain between the two units. In 1963 when I was a kid I had a Lafayette 0.1 watt single channel CB walkie talkie. It wasn't the toy type, it had 10 transistors and a good double conversion superhet receiver. My friend had one too.
We could get about half a mile in thick forest, but between high hilltops, we once got 9.3 miles and the reception was quite clear. The 5 watt units would have better range. If Cooper had an accomplice positioned on a mountaintop, and Cooper had a line of sight to that peak, it is VERY likely that they could talk to each other for 10 miles or more with cheap (30-80 dollars) CB walkie talkies of that era. That still leaves a serious problem arranging a rendevous since Cooper could probably not tell exactly where he was. Being able to communicate is not the same as being able to locate.
(This post was edited by 377 on Feb 7, 2008, 12:24 PM)