Question

Why do the pictures obtained on t.v. shake when an aeroplane pass from above at a low height?

Answer 1

because it disturb the communication.

Answer 2

Pictures obtained on T.V. shake when an aeroplane passes from above at a low height because of the interference caused by the low flying aeroplane.  

We get our T.V. picture through the wireless communication of signals. The direct signal coming to the T.V. gets reflected by the aeroplane and interference between the direct signal and the reflected signal happens resulting into disturbed T.V. picture.