Usually the aircraft config. **EXAMPLES BELOW**

These are taken by what your asking needed to be improved etc.

Menoverbillity

Example taken from Default Extra 300

[flight_tuning]
cruise_lift_scalar     = 1.0
parasite_drag_scalar   = 1.0
induced_drag_scalar    = 1.0
elevator_effectiveness = 1.0
aileron_effectiveness  = 1.0
rudder_effectiveness   = 1.0
pitch_stability        = 1.0
roll_stability         = 1.0
yaw_stability          = 1.0
elevator_trim_effectiveness = 1.0
aileron_trim_effectiveness  = 1.0
rudder_trim_effectiveness   = 1.0
p_factor_on_yaw          = 0.5
torque_on_roll           = 0.5

Increase flight speed

Example taken from Default 737

[Reference Speeds]
flaps_up_stall_speed    = 142.0                 //Knots True (KTAS)
full_flaps_stall_speed  = 113.0                 //Knots True (KTAS)
cruise_speed            = 477.0                 //Knots True (KTAS)
max_mach                = 0.82
max_indicated_speed     = 340                   //Red line (KIAS)