Sofia International Airport will suspend all civil flights during two short nighttime windows on February 23 and 24, allowing only military aircraft to operate, according to data published on Flightradar24 and an official notice to airmen (NOTAM). The restrictions will apply from 01:15 to 02:50 on February 23 and from 01:05 to 03:35 on February 24.

The temporary closure coincides with the presence of multiple US military aircraft at Vasil Levski Airport and the nearby Vrazhdebna Air Base. Among them are Boeing KC-135R/T Stratotanker refueling aircraft from the 6th Air Refueling Wing at MacDill Air Force Base in Florida, as well as a C-130 Hercules transport plane deployed from the NATO base in Ramstein. Observers have been tracking intensified movements of American aircraft through Bulgaria since mid-January.

The Bulgarian Ministry of Defense confirmed that the aircraft belong to the US Air Force and stated that their deployment is linked to NATO’s enhanced vigilance activities, with personnel assigned to service the planes. The US Embassy in Sofia issued a similar explanation. Officials did not provide operational specifics, stressing that such details are not typically disclosed.

Speculation has circulated online that the aircraft movements are tied to possible US actions involving Iran, especially amid a broader buildup of American air and naval assets in the Middle East. According to international monitoring data, refueling tankers such as the KC-135 play a central role in extending the range of combat aircraft during long-distance missions. Former Deputy Foreign Minister Milen Keremedchiev noted that such tankers are routinely used to refuel fighter jets mid-air, recalling that Bulgaria’s F-16s were delivered from the United States with similar support. He also remarked that the scale of US military equipment currently landing in Bulgaria has not been seen for years.

Airport authorities, however, told Bulgarian National Television that the overnight suspension of civilian traffic is related to technical work on runway shafts, with the chosen hours reflecting minimal scheduled commercial activity. The designated time slots nonetheless allow full runway availability for intensive military movements.

The KC-135 fleet, operated by Air Mobility Command with support from the Air Force Reserve and Air National Guard, has been in service since the late 1950s. Developed from the Boeing 367-80 prototype, the aircraft has undergone multiple upgrades over decades, including re-engining programs that improved fuel capacity, efficiency, operating costs and noise levels. Various modified versions have served in reconnaissance, airborne command and surveillance roles, while current KC-135R and KC-135T variants continue to receive modernization upgrades to communications, navigation and control systems to meet evolving operational and air traffic requirements.