Well I´ve been flying in fs2004 for about 2 weeks now, and haven´t even touched the LFS shortcut for a while.
This because it´s good time for flying now at winter when u can´t do anything else cos here isn´t even snow so it´s very hard to do any wintersports.
And I think that this is familiar for other player also: You CAN be bored on LFS. It happens in regular cycle.
U play LFS 2 months; u get fed up with it and play something else for a month. Then LFS feels kind of new and fresh cos u have played something else lately.
Well at least thats how it goes for me