Surviving an unplanned stay in a remote or wilderness location depends on many things.   Weather, terrain, geography and health all play their parts.  You can improve your chances of surviving in the wilderness by preparing a survival package and keeping it with you when the chances of an emergency sojourn in the wilderness are present. 

An example is flying in a small plane.  The Canadian Aviation Regulations (CARs) state that any flight travelling more than 25 nautical miles from and aerodrome must carry emergency survival supplies. The CARs sets out  a minimum list: you must have the means to start a fire, provide shelter, provide or purify water and visually signal distress.  

If you were to go on a sight seeing trip around Vancouver, or Whistler (or for that matter, just about any mountain resort in Western North America) you run the possibility of being stranded in very difficult terrain.  If you fly your own plane you also run this risk.  The CARs list is a good start, but its not extensive, and its pretty vague.  

Imagine you are on a day hike and get lost.  Again, in many parts of North America you can get into some very dangerous situations if you're not prepared, especially if the weather turns or you injure yourself.

A simple boating or fishing trip can also become an emergency.  A day of hunting can easily turn into a night in the woods.   

With situations like these in mind its pretty easy to come up with a list of survival gear to keep handy to minimize the risk of discomfort and even death if we're forced to spend a night or two out of doors.

Start with a backpack that is comfortable to carry and large enough to hold everythig you need. Get a dedicated one who's only role is the survival pack. That way you won't be tempted to empty your survival kit in order to go on a picnic. 

Survival experts who are well acquainted with bushcraft will tell you that you can live for three weeks without food, three days without water, three hours without shelter, and three minutes without air.  We'll assume that a survival kit is unlikely to keep you breathing if, for some reason, you stop, so perhaps the most important issue to address is shelter.  Include a light plastic tarp measuring 8' x 8', and 100' of light rope.  In a worst case scenario you can wrap yourself in the tarp, and in easier circumstances you can string up a nice shelter.  Three feet of the tarp on the ground and five feet doubled back overhead can keep you and your gear dry and off the ground in a pinch.

Include a knife, a hatchet and a coiled cable saw to cut the rope, firewood and poles.  

Make sure you include emergency fire making supplies, including matches, tinder, and some candles. Candles provide light, but they are also great for starting fires.

Include a headlamp with good batteries.  They're light and very useful.

You aren't likely to put a sleeping bag in a survival kit, but there's nothing wrong with including a space blanket, which will help keep you warm.

A water container also has its place. If you're in arid country fill it with water before you leave.  Water purification tablets may be a good idea.  In much of Canada they aren't really used, despite widespread giardia, but in some areas they are a requirement.   A small pot, or billy can, with a wire handle that allows you to hang it over a fire, or lift it out of a fire with a stick will purify water by boiling, and will make the luxury of tea or coffee a possibility.

Some energy bars won't hurt. They don't go bad and will provide much need calories.  You could also include some dry soup mix.

Don't forget that the emergency may start with an injury.  You won't be able to take a complete hospital, but some aspirin, a tensor bandage, sling and bandaids  are a must. 

When it comes to visual signals feel free to carry a flare, but more importantly, educate yourself about how to create large visual signals that can attract attention and be seen form the air.

All of this put together won't fill most day packs, but if you get a slightly bigger pack you can also throw in the things you really need for each trip (fishing tackle, lunch, cameras).  By being able to combine them you'll tend to take the survival stuff on a regular basis.  Hopefuly you'll never need it, but if the day ever comes that you do you'll be very happy that you took the time to put it together (especially if you include a satellite phone!)