There are now more than 50,000 applications related to travel available for the iPhone. Here are a few of the travel apps recommended by National Geographic Traveler magazine’s September issue as being among the best:

• Flight Track, offers real-time flight updates, delays and cancellations, while Next Flight helps you find options if you miss your plane.

• The Maps app, which is free, can be enabled to show traffic with green, yellow or red highways, depending on how many cars are on the road.

• Cheap Gas, a free app, gives you nearby stations and fuel prices.

• Trapster, also free, identifies speed cameras and known speed trap zones.

• Rest Area gives you a list of highway rest stops organized by how near they are to your location.

• Urbanspoon, which is free, queries a database to find nearby dining options.

• Currency, a free app, converts money between more than 90 currencies.