Three years after launching its first iPhone app, Priceline has finally included flights to supplement hotel and car rental bookings.

And, although William Shatner’s Negotiator character still appears as an image in the app, the app is now called Priceline.com: Hotels, Flights and Rental Cars. The app previously was called the Priceline Hotel & Car Negotiator App.

Such are the dynamics of the online travel agency business that hotels were the priority, and Priceline got around to including flights in the iPhone app three years after the app’s debut.

The iPhone app update includes the ability to book domestic and international flights on a published-price basis only. Again, the priority is hotels, which can be booked at published prices, via Express Deals [you know the rate but not the hotel name up-front], or Name Your Own Price [you submit a bid and find out the hotel name later]. The flight search gives you the option to indicate that you prefer non-stop flights, and then these options, if available, are displayed first.

In addition, Priceline’s iPhone app lists the departure airports closest to the user’s location, and also provides a list of the 50 most popular airports to streamline the search.

For registered Priceline users, the app optionally can fill in their billing information automatically to speed the checkout process.

Priceline says the updated app has been optimized for the iPhone 5’s larger screen size.