OK I know, horrible pun, but I just couldn't help myself. There are a plethora of travel related apps out there and it can be overwhelming to find what you're looking for if you aren't even sure where to start. I have used all but 3 of the apps I mention below, and hope to try out the remaining ones soon. This list is but a drop in the bucket of the world of travel apps, however it's a place to start if you need some direction!
Movies & T.V.- Amazon Prime and Netflix both offer offline watching now, and between the two you have endless options, so download away!
Music- Spotify also offers offline listening which is the perfect excuse to create a new playlist (or two).
Directions- My Maps by Google. Create a map online and download the free app to sync to your phone. While you can make edits to your maps via the app, you'll have limited options. While using your map offline you can zoom in close enough to see street names, and you can click on each point of interest you added to your map to see details of each location such as street view, address and any extra notes you added.
Gas- GasBuddy shows you gas prices where ever you are from all gas stations, including truck stops, Costco and grocery store gas stations.
Additional driving/walking apps to check out: Waze & Google Maps.
Lodging- Airbnb, Hostelworld, Dayuse and Hotels.com. Unless you only stay at a specific hotel chain (for points, personal preference, etc), these four options cover pretty much anything you're looking for.
Flight Deals- Skyscanner and Hipmunk are both very thorough and you can also use Hipmunk for hotel and car deals as well.
Trip Organization- TripIt and Google Trips. TripIt organizes all of your plans and reservations in one place. Google Trips also does that in addition to offering tips about the city you're in, and creating a travel guide based on the amount of time you have.
Phone Calls- Google Hangouts Dialer, Skype
Text- Google Hangouts, WhatsApp
Translator- Google Translate. Not only can you take a picture and have it translated, now Google Translate can translate in real time, just by pointing your phone at the text. You can also download a language for offline use!
Other- LoungeBuddy & XE Currency
I want to hear from you! What apps are you using? Let me know what I should be checking out!