Today in the middle of the flight from Portland to Amsterdam, I was unsatisfied with merely knowing what time it was in Portland and in Amsterdam. Instead, I wanted to know what time it effectively was in the airplane as I was flying, taking in to account the stretching of time by flying.
My theory is by looking at "airplane time" and ignoring the origin and destination times completely, it may be easier to adjust to a new timezone since you won't have to trick yourself into ignoring your other clocks.
So, on the flight, I put together an iOS app to show the local "airplane time" while on a plane traveling across many timezones.
Say you leave Portland at 1:30pm with a scheduled arrival time of 8:30am in Amsterdam. The app calculates a "local airplane time" based on the departure and arrival times and timezones. At the beginning of the flight, airplane time and Portland time are the same, but by the time you reach Amsterdam, airplane time matches the local time.
In order to accomplish this, flight-seconds must be stretched or compressed depending on which direction you're flying. When flying east, flight-seconds are shorter than real seconds, and when flying west, flight-seconds are longer.
You can download the source code for this app on Github! Feel free to send pull requests or file issues if you find anything broken!