Hello everybody, 
it may sound silly, but I simply cannot understand why when calculating
fixed effects panel estimation, some variables are "omitted due to the
collinearity" and the constant remains. Should not also constant disappear
from the estimation - as it bears the fixed effects???
I am calculating log-gravity models and the important variables are
omitted. What do I do wrong? 
How can I get know the coefficient of omitted variables? IT IS IMPROTANT
FOR MY ESTIMATION?

Thank you for your help. 

Iveta