After the high-speed SR-71 Blackbird retired in 1998, the Air Force has long debated for its replacement. No progress toward that goal was made and that’s because the RQ-180, a highly classified aircraft, has been developed by Northrop Grumman secretly.

According to Aviation Weekly‘s Senior Pentagon Editor Amy Butler and Senior International Defense Editor Bill Sweetman, the spy unmanned plane, is now in the flight testing phase and will be ready as soon as 2015.
The Northrop Grumman RQ-180 has been in development many years, perhaps as early as 2006, without anybody knowing about it.
Pentagon's new secret super-spy plane 1
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