Supposedly, this is a civilian airplane, and another user pointed out the oddity in a comment. The author of the answer then replied that [those missiles] "are as real as this being a USAF L-39 ;)". This second picture shows an airplane with "United States Air Force" painted on it. Does this mean that it is perfectly legal for a civilian aircraft to mount some fake missiles? And to write "USAF" on an airplane that doesn't belong to the USAF, even? Especially considering this airplane can really be configured as a military one, with real missiles!
To me this looks like going through security checks at the airport with a fake gun in your hands. Sure, it's fake and it can't harm anyone, but I'm not sure the police would appreciate my sense of humour.
Seriously, is this allowed? With all the attention to security (which often borders on paranoia), it is allowed to fly around with fake missiles? Won't this lead to unnecessary confusion, fear, and even false alarms?