How much does it cost to fly a Boeing 747-400 for 1 hour?

The Boeing 747-400 is both more expensive and less expensive to operate than modern aircraft with fuel spikes adding to the cost range.
Flightglobal

Operators of IAI-converted cargo 747-400s told to check oxygen hoses for chafing

Safety regulators have instructed operators of certain Israel Aerospace Industries converted Boeing 747-400 freighters to check wiring in the vicinity of cockpit oxygen hoses for potential risk of ...
Flightglobal

Speed-data entry error preceded 747-400F’s undetected tail-strike

German investigators have disclosed that an Air Atlanta Icelandic Boeing 747-400 freighter captain entered an incorrect rotation speed into the flight-management system, before the aircraft sustained ...