It flew low on the 90-minute journey, hugging the mountainous landscape and skimming over forests as if anxious to avoid radar detection.

There was no sign that it was evading radar detection or that it had been taken over by remote control.

Ways of foiling them include radar detection and electronic interference.

Though successful, the system was not put into production because of improvements made to radar detection.

Others have raised doubts about the use of canards on a low-observable design, stating that canards would guarantee radar detection and a compromise of stealth.