the author of this app says:
This is an electronic navigation log for VFR pilots. The two programs NavPlan and NavLog can be installed on a Palm OS handheld computer. NavPlan is used for flight planning whereas NavLog performs the actual follow up during the flight.
This tool lets you perform flight planning on an electronic navigation log similar to the well-known planning on Jeppesen or Cessna NavLogs. You can calculation climb- and descent-performance including time, distance and fuel burn to assist you with accurate fuel planning.
There is an on-screen map of the flight along with flight-related parameters. This comes with specifications for eight different aircraft types. You can even save several routings.
From a follow-up perspective, this tool provides block and flight time, true course, magnetic heading, remaining flight time and distance to next waypoint or destination. It calculates actual fuel on board and estimated FOB at destination along with an analysis of the flight including average fuel flow and speed.