Air travel is certainly not a one-type or size fits all. At the airport I get to see an incredible range of travelers - from families to sports groups, from unaccompanied minors to women in full abayas, there really isn't a cookie-cutter shaped passenger. Given this, airlines do have plans on how to assist passengers who may need it for the air travel experience.
Fear of Flying - First Time Flyer
The first thing that comes to mind regarding passengers who may require assistance are those who are afraid of flying, or first time flyers. It is okay to be afraid of flying, there is certainly a loss of control when you are sitting in a narrow seat, 30,000 feet above the earth, and the plane is shaking through an area of turbulence. There are courses for fear of flying, and many of them boast a solid success rate. I wasn't always the best flyer as i despised turbulence, and my method though unconventional, was to learn how to fly in order to overcome my fears (there certainly is nothing like bouncing around in turbulent air in a two-seater Cessna).
If you are afraid to fly, let airline staff know. At the gate, and even at check-in, I have done on the spot talks with nervous flyers to help them feel a little more at ease. You can often find a sympathetic flight attendant who will come by every so often to check in on you.
Again, there are fear of flying courses available. As another option, you can seek medical advice regarding prescribed medications to help deal with the anxiety of flying.
Do not feel afraid to ask questions. Yes, there are some surly airline employees, but the majority of those who work for airlines love to travel and do have a modicum of compassion for those who are afraid to fly. Years back, British Airways was one of the airlines that pioneered a project where employees would volunteer to fly with passengers who required assistance; dozens of airlines such as Air Canada operate flights that take underprivileged or ill children to places like Disney World, all on volunteered time. These are people who have a passion for people and travel so ask us! I often liken turbulence to hitting a pothole, or I ask a passenger to try and envision it as being rocked to sleep on a long flight (doesn't always work, but the effort is to diffuse the fear of the unknown).
Bringing along items of comfort may also help. Tranquil music on your MP3 player, or a really great pillow and fleece blanket can sometimes help take the edge off of fear. A tennis ball can be great for squeezing in your hand to relieve tension; plus it has the added bonus of keeping your carpal tunnel engaged so it can act to prevent swelling in your wrist and fingers during a long flight.
Sometimes reading up on weather conditions can help. Sources such as the FAA's Flight Delay Information - Air Traffic Control System Command Center can be really useful. Again, removing the unknown elements of flight can often alleviate a fearful flyer's anxieties.
Ultimately, when it comes to a fear of flying, know that you are not the only one who feels this way. I have had passengers faint in front of me, hyperventilate, and cry - one sees the whole range of emotions and autonomic responses working at an airport - there are those who are simply terrified of flying. However, with reassurance and preparation many do overcome the fear of flying and then can experience the world from all different time zones.