HEY! As I recall there was some bright wig that patented a scheme for using bags attached to the hind quarters of farm animals to collect the gasses while bypassing the solids. The aim being to harvest the noxious fumes to use as "natural" gas for fuel.

Of course this begs the question of what happens if some dullard farm hand attaches the cow size bags to sheep. Is the methane or any other gases lighter than air? Will be be inconvenienced by flocks of floating sheep during our relaxing drives in the country to reach our flying fields?

As for #2 about heavy planes..... There's no doubt that a heavier model will react to velocity changes due to turbulent conditions with less effect than a lighter model. But being heavy brings its own price in terms of good flyability. On the other hand a truly light model is only at its best in calm to light tubulence.

Note that I said "turbulence" instead of "wind". If the wind is smooth and steady overly light or overly heavy models will still work just fine. It's when thing in the sky turn to conditions such as found in washing machines that having a slightly heavier model can become a good thing.