As you might expect, some of the best apps for mobile devices such as smartphones and tablets are all about being mobile. A well-designed travel app — one that doesn’t require a lot of Internet connectivity on the road but that has lots of up-to-date information you can use — can mean the difference between a frustrating vacation meltdown or a breezy road to paradise.

I queried jet-setting travel-expert friends, scoured app ratings and reviews, and compiled this list of some of the best, most useful travel apps. Many of these have website versions as well; if you’re using a desktop or laptop computer, it doesn’t mean you can’t use some of them.

But the mobile app experience tends to be where many of these excel; having the info in the palm of your hand while you’re en route tends to beat dealing with printouts and Web browser bookmarks. All of the apps listed are free to download and use unless otherwise noted.

•  Booking and planning ahead

My go-to travel services used to be Orbitz and Travelocity, but the names that I keep hearing now for booking flights, hotel and other travel services have changed. Kayak (for iPhone/iPad, Android, Windows Phone and Kindle Fire), Hipmunk (booking without the ad clutter, for iPhone/iPad and Android), Booking.com (iPhone/iPad, Windows Phone and Android), Jetsetter (free with membership sign-up, for iPhone/iPad) and Hotel Tonight (for last-minute hotel deals) seem to rule the roost now among tech-savvy travelers.

If you’d rather stay at a home than a hotel, the two apps you should use for nontraditional lodging are Airbnb and HomeAway.

Looking for information on cruises? There’s Cruise Finder from iCruise.com for iPhone/iPad and Android.

Once you’re got your trip booked, the app I got the most recommendations for is TripIt (iPhone/iPad, Android, BlackBerry and Windows Phone 7), a travel assistant app which works with a wide range of services to consolidate all your travel information into easy-to-browse itineraries. A $49-a-year pay service, TripIt Pro, offers even more options for frequent travelers. An alternative app would be TravelTracker, which also organizes flights, hotel and car rental information. It’s free for iPhone/iPad with a Pro version for $10.

There are far too many to list here, but depending on your airline, hotel chain, car rental company and destination, it’s likely you can download individual apps for each of them. There’s a Jet Blue app, for instance, a W Hotels app and an exhaustive app for Walt Disney World with lots of useful information and in-app booking options (at Disney resort restaurants, for instance). Do a search for apps like these specific to your trip and grab them even if you’re not sure you’ll use them on the road.

•  En route

More apps to keep your blood pressure level down while you’re actually at the airport or flying include the cleverly named App in the Air for iPhone, GateGuru (for iPhone/iPad, Android and Windows Phone), TripCase (iPhone/iPad, Android and mobile Web browser) and the simple flight information finder FlightBoard ($3.99 for iPhone/iPad and Android).

Road tripping? The free GPS-powered traffic app Waze (iPhone/iPad, Android, Windows Phone and BlackBerry) is hugely popular. Hourly car rentals are available from other users through the app GetAround for iPhone. You can get the cheapest gas prices with the GasBuddy app (for iPhone/iPad, Android, Windows Phone and BlackBerry).