WARNING: Never attempt to operate an aircraft without proper instruction from a Certified Fight Instructor. It would be hazardous to your life.If you find yourself frequently flying in small aircraft as a passenger and would feel better knowing how to land it, organizations such as the AOPA (Aircraft Owners and Pilots Association) could refer you to flight schools which offer "Pinch Hitter" courses. These courses give you the basics in aircraft operation, an understanding of how to land a small plane, and how to get help. This knowledge will get you on the ground. It might not be pretty, but you'll walk away.
The question is "How do you land an airplane?" First of all, the chances of you being asked to land an airliner are zero, zip. It only happens in Hollywood. I would need to write a full sized novel to tell you how to land a commecial airliner. We will therefore limit this discussion to small, private aircraft.
So there you are staring out the window as the pilot finishes off that three day old turkey sandwich and keels over. What do you do?
Step 1: Communication
Let's face it, you need help. The pilot was probably wearing a headset. Take that headset and put it on. If he wasn't, then you have already been listening to the Air Traffic Controllers (ATC) that your pilot was talking to on the cabin speaker. There are usually two ways to transmit to ATC. Commonly, there is a button on the pilot's control wheel called a push-to-talk switch. There is also a hand microphone usually mounted somewhere in the cockpit within easy reach of the pilot. Use the hand microphone. To use the push-to-talk switch would require reaching across the pilot. Also, there could be other buttons on that control wheel such as the autopilot disconnect button (if one was installed and operating). So pick up the hand microphone, hold it very close to your lips (any closer and you'll kiss it), press the button on the side, try to speak in a normal tone of voice and make a simple request for help, then release the button. (If you don't you will continue to transmit and never hear a response). Once you have established communication with ATC, they will quickly realize the problem and do everything they can to help you. The one thing they can't do is fly the airplane, so what's next?