Hi folks.
I am engaged in development of the flight model for my company. I tried to use CFS one as a base. But some problem arised. My test pilot says, when in flight, with throttle off, the model decelerates too slowly. That is not a realistic thing. I tried to customize the entries in an air-file,  but all in vain. What can I do to increase the speed dumping in level flight?

In the .air file; look for the heading 'Flight Dynamics'. Under 'Flight Dynamics'; look for 'Fuselage drag' and increase accordingly.
If that doesn't seem to make an adjustment; then likely the aircraft's .cfg file will have a drag heading. The aircraft.cfg file modifies or in some cases overrides the data in the .air file; so if your modification of the .air file doesn't work; then it's in the .cfg file.
Cheers!

It's there - if you click on 'Flight Dynamics'; all the options within that heading will open up. Fuselage Drag will be near the top.