Editor: Mac Flight Planner is the only flight planning software designed for use by real pilots for real flying on Mac OS X. All other flight planning software on the platform is designed for use with X-Plane, in my opinion, the best flight simulator around, but still a sim.
Mac Flight Planner is (as the name implies) a flight planning application. In fact, Mac Flight Planner (MFP) is the only flight planning application for Mac OS X for use in real world aviation. All other flight planners on Mac OS X require the X-Plane database are are designed for use with that simulator. While X-Plane is, in my opinion, the greatest flight simulator going, I think you'll agree that it's database can't be relied upon for real world aviation around the world.
In MFP, you Create your own waypoint database. Yes, this can be tedious at first, but considering that most GA pilots will regularly use 20-30 waypoints in their immediate vicinity and then add a handful everytime they fly somewhere new, this task of creating and maintaing your own database is a lot less work than it may appear. Considering the alternative of paying huge sums of money for tens of thousands of waypoints you'll never use, it's not a bad trade-off.
So what can MFP do for me?
MFP lets you create flight plans you can print for in-Cockpit use through simple drag and drop. Enter true airspeed and wind heading and speed for each leg and MFP will computer wind corrected magnetic heading, ground speed, Distance, time interval and total time. You can also record Altitude and lowest safe altitude for each leg. You can see totals for the time of the flight, distance and total nautical air miles (amount of air you've travelled through).
You can enter a departure time and date and MFP will compute your departure time in UTC, arrival time in local and UTC, and whether you will be arriving or departing before or after sunset. You can also see the exact Sunrise and sunset times for your departure and arrival airports.