Well I rather like the method used in the article supplied by Kev...
the only thing I wonder is if the tripod is going to be affected by
pitch and bank, I guess the two bungee cords will hold it against
lateral and probably verticle acceleration, but I want to be sure it's
going to be okay when the plane is banking about 20 degrees.

Also, I don't want to use the spnge method because I don't want the
standard "over the dash" shot that you see in many cars and planes, I
want to use my 0.5X lens and get the shot from just above eye level
from the back seat, so you can see the instrument panel and out the
plane and me and any pax/other pilot sitting up front, a better angle I
think.