There's no shortage of apps for drone pilots out there, but here are a few that we really like, and recommend. (Note: we did not get a commission from any app developers - these are our true opinions of these apps.)
1. Drone Pilot - $39.99 on the Apple app store.
This an app (paid) for Canadian drone pilots that gives you reliable data on whether it's legal to fly where you are (in terms of proximity to airports). If you have your Advanced Operations designation, it offers you "NOTAM" information. It allows you to upload PDF versions of your Pilot Certificate and your drone Registration Certificate for easy access if you're asked to present it. It has weather radar too. It comes with a whole host of checklists, such as pre-flight, post-flight, etc. All based on Transport Canada requirements. Best of all, it has a very easy flight and maintenance log function, eliminating the need for paper log books.
2. UAV Forecast. Free, with in app purchases.
This is the best weather app for drone pilots out there. Enter your aircraft's manufacturer recommended weather limits (such as windspeed and temperature) and when you open the app, you can see in an instant whether it's "Good to Fly", along with lots of other relevant weather data, including sunrise/sunset, temperature, wind speed and direction, with gust speed, probability of precipitation.. It offers a forecast by hour for upcoming days so you can plan your flying based on weather. It offers a wind profile, which shows the windspeed at various altitudes. They also offer a desktop version. This is a must have for flying safely.
3. Litchi. $31.99 on the Apple app store.
Litchi is the best non DJI app for DJI drones. It allows you to plot out waypoints from home and then go out and fly them. It also has the ability to connect to VR goggles for an extraordinary experience while flying (although we do recommend having a ground observer keeping an eye on your drone while you fly with goggles on). In VR mode you can turn tilt your head to tilt the gimbal! Litchi is a very advanced app and has a tremendous amount of great features, but if you're looking for something you can fly with besides the DJI apps, this one does a great job - many pilots prefer it.
4. One final recommendation, which is not an app, but rather a desktop client, is Air Data UAV. They offer a limited functionality free subscription, and several tiered paid subscriptions. After you fly, you can sync your flight records (using an app called "HD Sync") and view all the data your aircraft has collected. It's a great way to see the status of your batteries, including percentage life, number of charge cycles, and any imbalances in the cells. It has great recommendations on service intervals and tells you when to do what based on number of hours / flights. You can then log your maintenance service and it will start counting again. You can view any error messages you received (that you may have missed) and spot any potential issues with your drone or batteries before they turn catastrophic.
These apps / websites will have you totally set up to be a safe, aware drone pilot.