Hey it's an interesting to do it....
I think these r some tutorials might help ya..
http://www.3d-palace.com/xenomorphic/ed ... clouds.htm
also don't forget to check out his site..
http://www.xenomorphic.co.uk
and yeah just one suggestion..don't keep ur camera steady...or follow it with the speed of plane...that makes ur plane so steady ...
check out some references movie on
http://gettimages.com