($4.99 for iOS and Android phones; $9.99 for iOS and Android tablets — for iOS 6.0 or Android 4.0 and above)
What it is: A mobile version of Adobe Photoshop that provides a complete set of photo-editing tools on an iOS or Android phone or tablet.
How it works: You create projects using images stored on your device. You can click on tools to crop or adjust shadows and highlights or color balance and more. Other tools help you add effects, create a photo collage, a painting, etc. Because Photoshop has so many tools, I found the PS Touch tutorials very helpful.
Why it's great: With PS Touch on my iPad, I can leave my laptop at home. The app offers photo edits and touch-ups on the fly. On long flights, I can create a collage or get artsy. I primarily use PS Touch on my iPad because I prefer editing on a larger screen. But for quick edits, I also use PS Touch on my iPhone 4S.
Why you might hesitate: You hate tutorials. But before skipping this app, watch a few YouTube videos that demonstrate the power of PS Touch.
(Free for iOS, Android, Windows, BlackBerry and Nokia)
What it is: An app to identify music and other media, including songs, TV shows and TV advertising.
How it works: You launch the app and press the Shazam button. Shazam listens to the music or TV show playing nearby, then uses a data connection to identify the song or show. If you are in a bad reception area, it can store a digital fingerprint to identify it later.
Why it's great: When you recognize a song but can't recall the title, Shazam eliminates brain freeze. Its Pulse feature reveals the top trending songs, tagged in real time, so you can check out the hottest tunes around the world. Before a trip, you can use the explore map to find what's popular at your destination, so you land tuned in. After Shazam identifies a song, you have options to buy it, see lyrics, listen to it on Spotify or watch a YouTube video featuring the song. For TV shows, Shazam provides cast info, music in the show and more.
(Free for iOS, Android, Windows phone and BlackBerry; custom version for iPad)
What it is: An app from Delta Airlines for booking and tracking Delta flights, with extra features, including upgrade tracking, parking reminders and baggage tracking.
How it works: After setting up the app with your Delta SkyMiles number, you can book flights, check flight status and track bags from the home page. To track bags, you scan or type your bag tag receipt number. By clicking My Delta, you can access your electronic wallet with payment methods, receipts and an e-version of your SkyMiles membership card
Why it's great: Nothing is worse than landing without your luggage. So for me, bag tracking was love at first sight. When I connected in Memphis, Tenn., on a recent Delta flight, I scanned my baggage receipt, and Fly Delta showed me that my bag had been transferred to my plane. I flew worry-free to LAX, knowing my bag was aboard. The app is intuitive, and I love that My Delta stores my trips, my profile and SkyMiles status. Under travel preferences, I can store my preferred airport, seat preference and meal requests.