The Nigerian Airspace Management Agency (NAMA) has announced plans to increase the unit rate/minimum charge for en-route air navigation services from N2,000 to N18,000.Umar Farouk, managing director (MD) of NAMA, spoke on Friday at the League of Airports and Aviation correspondents seminar in Lagos.The event was themed ‘Aviation Survivability amidst a Challenging Macro-Economic Environment’.Farouk said the unit rate/minimum charge for terminal navigation charge (TCN domestic) would also be raised from N6,000 to N54,000 per flight.