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

        for (Airport a : getAirports()) {
            if (a.getCity().contains(searchString)) {
                result.add(a);
            } else if (a.getCountry().getCountry().contains(searchString)) {
                result.add(a);
            } else if (a.getName().contains(searchString)) {
                result.add(a);
            } else if (a.getCode().contains(searchString)) {
                result.add(a);
            } else if (String.valueOf(a.getId()).contains(searchString)) {
                result.add(a);
            }
        }

        return result;
    }