The seven optimized travel apps and Apple’s Passbook.

Apple’s Passbook app received minor tweaks in the new OS.

Hipmunk was first out of the gate with its updated app. While its flying chipmunk mascot is still the lead image, it gives more real estate to hotels on the homepage and puts booking front and center on profile pages.

Starwood Preferred Guest rolled out its first iPad app yesterday, but also gave a little flat love to its iPhone app.

Hotel Tonight uses shaded overlays and wider images in its updated app.

You don’t need LoungeBuddy often, but when you do it’s an indispensable source of info on where to relax in airports. It’s also done flat well.

US Airways customers are praying for the American Air merger to go through in hopes that it will free them from US Air’s utterly terrible app. American Air didn’t disappoint with its iOS 7 update — like a confident product that knows what it’s doing it eschews branding for usability.

Expedia vassal Travelocity beat it’s new master out of the iOS gate with an incredibly friendly app that focuses on tonight-only and other hotel booking. It’s the most Apple-feeling of its app peers.

OpenTable’s app is clean and fast, making discovery and booking at its participating restaurant rather seamless.

Yesterday Apple released updated operating system for its iPhone smartphone and iPad tablets, and most of the big travel companies were ready with updates to their apps.

While none of the apps were able to take advantage of upgrades like the new fingerprint sensor on the iPhone 5s, most of them took design cues from the new design language of iOS 7 to deliver flatter apps with muted color palettes. Gone also are the icons with shadow effects that defined their look for the first six years of the iPhone.

Apple is featuring seven travel-related apps as “Designed for iOS 7.” Brands that have yet to update their apps to the new look will still work, they’ll just look slightly different.

The world’s most popular travel app works on iOS 7, but has yet to be re-designed.

Click through the slides above for a look at the seven, as well as Apple’s updated Passbook.