If you’ve ever flown United to Hawaii you’ve probably played the Halfway to Hawaii game. This application computes your estimated halfway time based on air speed, headwind, total distance, and takeoff time. You’re already halfway to the prize!

You’ll need to adjust the time based on the complexity of the route and other factors as they determine the winner based on the actual time that they reach the halfway point. Generally you’ll need to add 5 to 10 minutes to the estimated time.

http://appshopper.com/travel/halfway-to-hawaii