As of Oct. 1, it has been seven years since MV-22 Osprey vertical takeoff and landing transport aircraft were deployed to the U.S. Marine Corps Air Station Futenma in 2012 and one year since CV-22 Osprey were deployed to the U.S. Air Force Yokota Air Base.

Flights by the U.S. military airplanes are restricted in the early morning and late night (from 10:00 p.m. to 6:00 a.m.). According to visual monitoring performed by the Okinawa Defense Bureau, however, MV-22 Osprey accounted for 29.8% of all flights by U.S. military aircraft during the hours of restricted flights in fiscal 2017. The ratio increased to 36.2% in fiscal 2018 and further to 48.7% in fiscal 2019 (as of August). This indicates that the number of flights made during the restricted-flights period has continued to increase steadily. Aircraft noise late at night disturbs residents in base-hosting communities. (Abridged)