I am able to compile and install flightgear development version in an Ubuntu 12.04, X server ver: 1.11.3, Kernel - 3.2.0-20-generic, x64bit by using below wiki.
Now, I am not able to fly the exactly same way as you mentioned in the youtube video
I tried to fly by using tutorials, but it is very slow and issue is not reproeing. And also, you mentioned all the settings as high.
Please also mention what are exactly those settings.