Zoltan - a good in-flight shot, it what looks like tough lighting conditons. I think the biggest problem here is the angle of the head - it would have been nicer to have the bird turning toward the viewer (but given the light angle, probably would have put the bird's face into shadow). Is this a large crop?
Head angle and steep angle are the top two concerns here. Good exposure for the sidelight you had. Jeff is correct about the HA / light angle issue...in this situation, if possible, it would be best to position yourself with the sun at your back. It appears to be a Sandwich Tern...didn't realize you had them over in Hungary too!