An apparatus, comprising: a trajectory planner adapted to produce a command position vector for a fixed-wing aircraft; a Trajectory Linearization Control ("TLC") architecture electrically coupled to the trajectory planner and configured to receive the command position vector from the trajectory planner; an avionic sensor electrically coupled to the TLC architecture and configured to send a sensed parameter to the TLC architecture; and a control actuator electronically coupled to the TLC architecture and configured to receive a control signal from the TLC architecture; wherein the TLC architecture includes: a processor; and program code configured to be executed on the processor to generate the control signal by: determining, in a first control loop, a nominal body velocity vector and a feedback control body velocity command vector using the command position vector from the trajectory planner; determining, in a second control loop, a nominal Euler angle vector, a feedback control Euler angle command vector, and a throttle setting feedback control command using the nominal body velocity vector and the feedback control body velocity command vector from the first control loop; determining, in a third control loop, a nominal body rate vector and a feedback control body rate command vector using the nominal Euler angle vector and the feedback control Euler angle command vector from the second control loop; determining, in a fourth control loop, a moment command vector using the nominal body rate vector and the feedback control body rate command vector from the third control loop; and determining the control signal using the moment command vector from the fourth control loop. a trajectory planner adapted to produce a command position vector for a fixed-wing aircraft; a Trajectory Linearization Control ("TLC") architecture electrically coupled to the trajectory planner and configured to receive the command position vector from the trajectory planner; an avionic sensor electrically coupled to the TLC architecture and configured to send a sensed parameter to the TLC architecture; and a control actuator electronically coupled to the TLC architecture and configured to receive a control signal from the TLC architecture; wherein the TLC architecture includes: a processor; and program code configured to be executed on the processor to generate the control signal by: determining, in a first control loop, a nominal body velocity vector and a feedback control body velocity command vector using the command position vector from the trajectory planner; determining, in a second control loop, a nominal Euler angle vector, a feedback control Euler angle command vector, and a throttle setting feedback control command using the nominal body velocity vector and the feedback control body velocity command vector from the first control loop; determining, in a third control loop, a nominal body rate vector and a feedback control body rate command vector using the nominal Euler angle vector and the feedback control Euler angle command vector from the second control loop; determining, in a fourth control loop, a moment command vector using the nominal body rate vector and the feedback control body rate command vector from the third control loop; and determining the control signal using the moment command vector from the fourth control loop. a processor; and program code configured to be executed on the processor to generate the control signal by: determining, in a first control loop, a nominal body velocity vector and a feedback control body velocity command vector using the command position vector from the trajectory planner; determining, in a second control loop, a nominal Euler angle vector, a feedback control Euler angle command vector, and a throttle setting feedback control command using the nominal body velocity vector and the feedback control body velocity command vector from the first control loop; determining, in a third control loop, a nominal body rate vector and a feedback control body rate command vector using the nominal Euler angle vector and the feedback control Euler angle command vector from the second control loop; determining, in a fourth control loop, a moment command vector using the nominal body rate vector and the feedback control body rate command vector from the third control loop; and determining the control signal using the moment command vector from the fourth control loop. determining, in a first control loop, a nominal body velocity vector and a feedback control body velocity command vector using the command position vector from the trajectory planner; determining, in a second control loop, a nominal Euler angle vector, a feedback control Euler angle command vector, and a throttle setting feedback control command using the nominal body velocity vector and the feedback control body velocity command vector from the first control loop; determining, in a third control loop, a nominal body rate vector and a feedback control body rate command vector using the nominal Euler angle vector and the feedback control Euler angle command vector from the second control loop; determining, in a fourth control loop, a moment command vector using the nominal body rate vector and the feedback control body rate command vector from the third control loop; and determining the control signal using the moment command vector from the fourth control loop.