The planes' operations come as part of the wider Exercise Agile Liberty, where close air support procedures making use forward air controllers and the tactical command of air-to-air air operations with observers are to be rehearsed.

The visit is the second in a little over a month from the distinctive, twin-engine, twin-seat, twin-stabilizer McDonnell Douglas F-15E Strike Eagles; several were at Ämari as part of the Baltic Trident Exercise in March.

The exercises will center in the vicinity of Ämari air base and also over Saaremaa and Hiiumaa, though not at particularly low altitudes, with the planes a minimum of 1,500 meters high at all times, BNS reports.

The F-15s are coming from the USAF's 48th Fighter Wing's home of RAF Lakenheath in the U.K., while they will be based at the 32nd Air Base in Lask, Poland, while Agile Liberty is ongoing.

The U.S. regularly conducts such exercises to assess readiness and/or to fulfill security responsibilities and boost NATO training capabilities.

As a result, NATO member states set aside airspace for use in the drills, which is precisely what Estonia is doing Wednesday, in conjunction with the civilian Transport Administration (Transpordiamet) and air traffic control.