Suggestions for additional features
- Track the distance the player flies in each game, and save the maximum value as a high score.
- Increase the speed incrementally as time goes on or include boost items that increase the plane’s speed.
- Flying obstacles that need to be dodged, such as other planes or birds.
- (Advanced) Instead of only straight lines, add curved chunks as well. The player will have to steer and the camera will have to move to stay behind them.
This would also be a great game for you to experiment with building a game for a mobile platform. See the next chapter for information about exporting games.