For VTOL FW rate controller is configured in MC mode (because in this mode pitch and yaw are controlled by FW controller).
In fixed-wing mode PX4 assumes that FW-controller is configured for FW_AIRSPD_TRIM.
But FW_AIRSPD_TRIM is also a speed in mission mode.

If I set FW_AIRSPD_TRIM to air speed during hovering, then in FW mode plane will go with very low speed.
If I set FW_AIRSPD_TRIM to desirable speed of mission, then FW rate controller will not work adequately.

Is it possible to separately set air speed for FW controller and mission cruise speed?

Ok, silly question, I can set mission speed in waypoint settings.