Japan and the US are expected to reach an agreement soon on new routes for commercial flights through US-controlled airspace over part of Tokyo and adjacent areas.
The measure is aimed at dealing with air traffic congestion expected at Tokyo's Haneda Airport in the run-up to the 2020 Olympics and Paralympics.
The Japanese government decided new routes are needed to allow more international flights at Haneda, and that the routes must pass over central Tokyo and nearby airspace controlled by the US Yokota Air Base.
But the US side rejected the idea, saying it might interfere with military air training.
Sources say the government was able to persuade US officials to accept that the Tokyo Games could be in jeopardy if the new flight routes are not opened.
The two sides plan to soon sign an agreement on the new routes through US-controlled airspace.
Government officials say they're confident the measure will also help reach the target of having 40 million foreign travelers visit Japan annually by 2020.