Complex sentence: Several aspects of the KQ-X program are considered revolutionary: not only will the aerial refueling be autonomous, but since Global Hawks are classified as HALE UAVs, the refueling tests will occur at an altitude higher than that typically performed using manned aircraft.
Split into simpler sentences: Several aspects of the KQ-X program are considered revolutionary. Not only will the aerial refueling be autonomous, but since Global Hawks are classified as HALE UAVs, the refueling tests will occur at an altitude higher than that typically performed using manned aircraft.