How to create a "lag" effect for a airplane

I am creating a flight sim controll scheme and am trying to figure out how to make a “turn lag” effect. The only way I can describe it is what happens when a hellicoptor comes to a stop from high speed. The rotation changes, but the inertia keeps the chopper moving forewards for a short time. What would be the best way to script something like this? I was considering using some sort of lag between rotation and velocity…

Are you using physics to control the helicopter? Can give a bit more detail about how you are controlling the helicopter and post any relevant code?

The airplane is controlled by user input off the three joystick axis, lerp’d for a smoothing effect. This input is read and I am using a transform.translate( ) function to move the ship. I tried adding force to the rigidbody, but that didnt work well at all, strange lag and other bizzare problems showed up. The transform.Translate is working fine (except for a problem with collisions, see my post in unitySupport), it has a very nice feel, I just want to go the extra mile and add inertia. The only way I can think of doing this is some sort of lag between rotating and translating the ship; but I’m not sure how to do this, if it’s even the right way.

EDIT:
Fixed the AddForce problem. I had it inside a Function Update instead of FixedUpdate, also changed it to AddRelativeForce. I think I’ll stick with this as it allows me to add drag, gravity and lift easier…