The international exercise Thracian Star 2014 is taking place at Graf Ignatievo Air Base between 26 May and 4 June. 
A wide variety of types is involved in the exercise, including MiG-21, MiG-29, Su-25 and L-39ZA from Bulgarian Air Force, F-16 from 148th Fighter Wing, Minnesota ANG, Romanian Air Force MiG-21 LanceR and Hellenic Air Force F-16.
The bulgarian and US planes are operating from Graf Ignatievo while the LanceR's and greek F-16's are flying from their home bases.