The most-watched aircraft on the flight tracking App Flightradar 24 are a Global Hawk unmanned spy plane and USAF KC135 and KC10 tankers.

The unmanned Global Hawk has been flying over the Black Sea just south of Russia’s naval base at Sevastopol while the KC135 (Boeing 707s) and KC10 (DC-10) tankers have been stationed over Romania and Poland.

Over 58,000 people are watching the activities of the Global Hawk which has a call sign of “Forte12” or “Forte11”.

The $170 million aircraft is piloted remotely and operates from Italy.

It has an endurance of about 32 hours and can fly over 22,000km at an altitude of 18,000m.