One of only 2 in existence: US 'Combat Sent' spy plane spent 30 hours in South Korea

The RC-135U Combat Sent, a strategic reconnaissance aircraft of which the United States operates only two, spent roughly 30 hours in South Korea before moving on to Okinawa, Japan, according to tracking data.

Voice of America reported Tuesday that flight-tracking website FlightRadar24 showed the Combat Sent entering the Korean Peninsula via waters off the southern coast on June 26 at 7:53 a.m., before being detected near Suwon, Gyeonggi Province, at 8:14 a.m. Its position signal then disappeared.

The aircraft reappeared on tracking data near Osan, Gyeonggi Province, on June 27 at 2:48 p.m. — roughly 30 hours later — and landed at Kadena Air Base in Okinawa, Japan, at around 5 p.m. the same day.

VOA described it as unusual for evidence of a US strategic reconnaissance aircraft staying in South Korea for more than a day to become publicly available. Whether the plane was on the ground or continued flying during the period when its position signal was absent remains unknown.

The Combat Sent is a specialized signals intelligence aircraft operated by the US Air Force, capable of collecting and analyzing ground radar emissions, military communications and various electronic signals from hundreds of kilometers away. It can also detect missile launch preparations and track the flight characteristics of ballistic missiles.

According to VOA, the Combat Sent is typically spotted over the Korean Peninsula two to three times a year. Most previous flight tracks showed the aircraft flying over the Military Demarcation Line area and airspace above the East and West seas before returning to Okinawa or other bases within a few hours.

North Korea has shown sensitivity to the activities of US strategic reconnaissance aircraft on the peninsula — in 2024, KCNA published a commentary criticizing the Combat Sent's deployment to the Korean Peninsula.