UFO or OVNI

Dear Friends
we all know that apparitions of UFOs i.e. Unidentified Flying Objects : http://en.wikipedia.org/wiki/Unidentified_flying_object or OVNIs i.e. Objets Volants Non-Identifiés : http://fr.wikipedia.org/wiki/Objet_volant_non_identifi%C3%A9
are rather uncommon and many images of them are the result of tricks made by
skilled photographers. So that, I was very impressed, on 30 December of the last year 2014, in leaving Frankfurt am Main by train for reaching Jean-Luc in Dusseldorf, to see above the cirrus a group of three UFOs, evidently patrolling the air space and the territory near Frankfurt. After having made an extensive turn above the train, the group disappeared to the horizon. I let to you, after seeing the images, to formulate and eventually to share them with me your considerations.
Happy 2015
Giancarlo

 Where is the trick ?????