Travelling internationally? The concierge at your hotel in Marrakech might not know if your afternoon flight is delayed, but FlightTrack will. This well-designed $5 app provides real-time information for departures, delays, and cancellations at more than 16,000 airports around the globe. It includes zoomable, live flight-tracker maps, weather forecasts, and even information on alternative flights. FlightTrack's offline mode allows you to view the app's maps even when you're not connected to the Internet, such as when you're cruising at 30,000 feet on a plane without Wi-Fi.