It has to do with AES installed. It does not matter if you havent activated in aes.
This trick also works with the afcad v4 files
First check if these files are set to off.
in the flytampas-copenhagen>scenery
jets_random.off
jets_static.off
AF2_EKCH_FSX(jets)_nw.off
AF2_EKCH_FSX(jets_random)_nw.off
AF2_EKCH_FSX(no_jets)_nw.off
after that open AES and doubleclick on flytampa copenhagen. So that the word off changes to fsx.
so that it looks like this.
http://puu.sh/g44tV/7fc626493a.png
So you dont have to spend credits on it. just set off to fsx. That's it!