I only have a problem with heights on top of a ladder where i don't have something to grab hold off if something happens.
In aircraft i have no problem at all, flown gliders before i started my cpl and now i'm flying on the line with a very bit of SEP in between.
The safety on an airliner is the highest in the world, there are a lot more accidents with cars, trains, boats and motorcycles as well then there are accidents with airliners.
If something happens to an airliner anywhere in the world you would most likely hear about it, but if someone gets a traffic accident and gets killed you maybe hear about it in the local news only.
It's not very likely that someone would die if you have a rapid depressurization and you put your mask on first and then help the ones next to you.
The time of useful consciousness at FL400 is 15-20sec (according to wikipedia) this doesn't mean that afterwards you will die, you will stay longer conscious but you are no longer useful (sounds a bit hard but the hypoxia starts to kick in). A few years ago there was someone who fell out of the wheel well of a B777 (not pressurized of heated) close to London, when they investigated his body the conclusion was that he didn't die in the aircraft, he was in some kind of hibernation.
It off course happens that some cracks are missed on inspection which causes depressurization but it's a very small percentage, a lot more cracks are found and fixed.
I hope this helps you a bit,