Germany has offered the Croatian Air Force 20 aging F-4 Phantom fighter planes free-of-charge, reports Croatian state TV HRT.

The McDonnell Douglas Phantoms will replace Croatia’s six Soviet-made MIG-21 jets, which are older than the F-4 Phantom planes, if the offer is accepted.

The twin-engine US-built F-4 fighters, which entered service with the US Air Force in 1960, can fly for another couple of years before they are retired.

If the offer is not accepted, Croatia could soon be left without jets to protect its skies.