Good question: what's next? Here are some possibilities:

- "Convenience" fee for those who wish to recline their seat back
- "Tray Table Usage" fee
- "Early Exit Fee": if you don't pay this fee, upon arrival you hafta remain seated until those who've paid the fee have deplaned
- "Illumination Fee" for using the overhead lights
- "Entertainment Fee" for fillling in the crossword puzzle
- "Information Fee" collected by FA's who pass the hat after every in-flight announcement made by the pilot
- "Time is Money" fee, where they charge you extra if the flight happens to arrive a few minutes earlier than scheduled
- "Takeoff Threshhold Fee" where they taxi to the end of the runway, then pass a hat to take up a collection. When the pool of money gets sufficiently large, the plane starts its takeoff roll.

Anyone else care to add possibilities to this list?