class AirDistanceRouter implements Router, DistanceCalculator, Region {

    @Override
    public long travelTimeMillis(Coordinates from, Coordinates to) {
        BigDecimal latDiff = to.latitude().subtract(from.latitude());
        BigDecimal lngDiff = to.longitude().subtract(from.longitude());
        double distanceKilometers = Math.sqrt(latDiff.pow(2).add(lngDiff.pow(2)).doubleValue()) * KILOMETERS_PER_DEGREE;
        return (long) Math.floor(distanceKilometers / TRAVEL_SPEED_KPH * MILLIS_IN_ONE_HOUR);
    }

}