I have two things to contribute that have not already been covered so far..
1-Basic aerodynamics download here:
http://67.161.249.237:8080/basicaero.ppt
2-And what to do when a plane goes down: Instructions-
Use the following methods to find a downed plane:
When a plane goes down and you think it might be a difficult search place your transmitter down on the ground (at your feet) with the antenna pointing in the exact direction that you lost sight. That marks the reference point and exact direction of the plane. You can then find a suitable replacement for the reference point and pointer (transmitter) before you trudge into the bushes. With a spotter at the reference point go directly toward the plane as pointed by the reference line. A spotter can guide you left or right as you deviate from the sight line.
By doing this you can walk right to the plane or its remains. Using the transmitter to make noise will help you to narrow the search area. Of course this must be the first method used after a crash. By the next day your mind will have muddied up the memory enough to make your search much more difficult. The key to a successful search (other than luck) is a well marked reference point and a line pointing to the crash site.
I learned this method of point marking when I was a life guard. Marking an event works well in when finding a swimmer who has slipped under the water or even deer hunting after you make a shot and need to search for the darn things. (we)(I) tend to wander in our searching without propper markers..