This morning I discovered a critical bug in When Pigs Fly that was causing aerodynamic forces on some objects to be calculated incorrectly. I have updated the game to 0.2.1, which includes a fix for this bug. You'll likely notice your aircraft generating more lift and more drag. In some cases, you may need to add more engines to counteract this drag.
I also included the new parachute and flywheel parts as a bonus. Get the update here.