Civil Aviation Minister Ajit Singh today justified the decision of the Airports Economic Regulatory Authority, AERA to hike user development charges at the Delhi airport for the next two years. Talking to reporters outside Parliament, he said AERA is a judicial authority and it has hiked the levy after consulting the concerned parties.Asked about Foreign Direct Investment, FDI, in the aviation sector, Mr. Ajit Singh said any decision will be taken only after a consensus among the concerned groups.