IF...You want to remove the co-pilot in a GA Aircraft

Find the aircraft.cfg file for the plane you want to play with...  (This will not remove the pilot)

Open the file, then go down and change this:

[PILOT]
pilot = "Pilot_Female_Casual"
copilot = "Pilot_Male_Casual"
instructor = "Pilot_Male_Casual"
pilot_default_animation = "Idle1_PosePropeller"
copilot_default_animation = "Idle2_PosePropeller"
pilot_attach_node = "PILOT_0"
copilot_attach_node = "PILOT_1"
 

To This:

[PILOT]
//pilot = "Pilot_Female_Casual"
//copilot = "Pilot_Male_Casual"
//instructor = "Pilot_Male_Casual"
pilot_default_animation = "Idle1_PosePropeller"
//copilot_default_animation = "Idle2_PosePropeller"
//pilot_attach_node = "PILOT_0"
//copilot_attach_node = "PILOT_1"

If you want to be even more OCD (like me), then open the flight_model_cfg   and zero out the weight of your copilot.  SEE the line for station_load.1    I changed the default 170 to 000.

[WEIGHT_AND_BALANCE]
max_gross_weight = 3650 ; Empty weight, (LBS)
empty_weight = 2600 ; Empty weight, (LBS)
reference_datum_position = 3.6, 0, 0 ; Position of reference datum relative to FS(0,0,0) (FEET), z, x, y
empty_weight_CG_position = -3.5, 0, 0.2 ; Position of airplane empty weight CG relative to reference datum (FEET), z, x, y
CG_forward_limit = 0.11 ; Gravity center forward limit in %MAX (divided by 100: 0.11 = 11%MAC)
CG_aft_limit = 0.32 ; Gravity center aft limit in %MAX (divided by 100: 0.32 = 32%MAC)
empty_weight_pitch_MOI = 3749 ; Empty pitch moment of inertia, Jxx (SLUG SQ FEET)
empty_weight_roll_MOI = 2352 ; Empty roll moment of inertia, Jzz (SLUG SQ FEET)
empty_weight_yaw_MOI = 5838 ; Empty yaw moment of inertia, Jyy (SLUG SQ FEET)
empty_weight_coupled_MOI = 100 ; Empty transverse moment of inertia, Jyz (SLUG SQ FEET)
activate_mach_limit_based_on_cg = 0 ; Activate mach limitation depending on CG position (true if > 0 /false othewise). Mostly for Concorde).
activate_cg_limit_based_on_mach = 0 ; Activate cg limitation depending on mach value (true if > 0 /false othewise). Mostly for Concorde).
max_number_of_stations = 7 ; Number of payload stations
station_load.0 = 170, -3, -1.1, 0.9, TT:MENU.PAYLOAD.PILOT, 1
station_load.1 = 000, -3, 1.1, 0.9, TT:MENU.PAYLOAD.COPILOT, 2
station_load.2 = 0, -6.2, -1, 0.9, TT:MENU.PAYLOAD.FRONT_PAX_LEFT, 4
station_load.3 = 0, -6.2, 1, 0.9, TT:MENU.PAYLOAD.FRONT_PAX_RIGHT, 4
station_load.4 = 0, -12, 0, 1, TT:MENU.PAYLOAD.BAGGAGE, 6
station_load.5 = 0, -9.6, -0.6, 1, TT:MENU.PAYLOAD.REAR_PAX_LEFT, 5
station_load.6 = 0, -9.6, 0.6, 1, TT:MENU.PAYLOAD.REAR_PAX_RIGHT, 5

Sometimes I just like to fly alone...   hahaha