public ArrayList<Airport> SearchAirport(String searchString){
        ArrayList<Airport> result = new ArrayList<Airport>();

        for(Airport a : airports.values()){
            if(a.getCity().contains(searchString)){
                result.add(a);
            }
            else if(a.getCountry().contains(searchString)){
                result.add(a);
            }
            else if(a.getName().contains(searchString)){
                result.add(a);
            }
            else if(a.getCode().contains(searchString)){
                result.add(a);
            }
        }

        return result;
    }