The much anticipated accession of Croatia to the European Union has brought with it a certain number of EU directives and regulations relating to the adjustments to be made by Croatia as a member country whose state border has become the external EU border with third countries, making the Schengen Acquis a reality for the Croatian border police as well. Regarding the topic of the paper, the elaboration of the application of Schengen rules has been limited to the air space, that of the Osijek Airport in particular, as the leading airport in Eastern Croatia. The accession of Croatia to the European Eunion has coincided with the need of the Osijek Airport for the economic recovery. Consequently the Airport, its construction space in particular, has to make necessary adjustments during reconstruction regarding the provisions stated in the Schengen Catalogue. The amount of work that the operator has to do is not negligible in relation to the whole new approach to the economic recovery and the transfer of passengers within the borders of the European Union especially their transit to third countries. It should be noted that during the reconstruction of the Osijek Airport particular attention was given to the Schengen Area space due to sensitive topics like migration, smuggling and prevention of terrorism. Regarding the delicate nature of the topic and confidentiality restrictions, many details will not be exposed in the paper. However it should be noted that series of analyses and risk profiling have been made and the space has been designed and the equipment procured accordingly. The process of adjustment of the Airport to Schengen standards will take as long as necessary to both fully adjust the space and train the personnel, according to the good practices of other airports.