Where is the weak point?

[uglijimus]

(sorry, i'm crossposting this just realizing that the original subforum is probably not as good as this one)

My wife and I just moved into a new house and realized that are house is probably right below a route for airplanes for an airport near our house.  From what I read, the windows are probably the weak point, but how can one tell?  I would hate spend a lot of money on soundproof windows only to realize it's the walls. (Ours are plaster by the way).  Any way of measuring where the sound leak is?

thanks

[Randy S]

Most of the time the windows are the weakest point due to lack of Mass, However with you in a flight path your entire house will be hit by the sound wave from the passing airplanes and the house itself will remit the vibration. When the planes pass over head where do you naturally look? at the windows or is the sound omni directional?