Behind the scences
Air traffic control looks after flights coming into and out of airports. Pilots make sure they follow set routes and fly at certain heights safely. Airlines do constant maintenance and countless checks on their planes. And aviation groups look over everything making new rules and giving warnings about issues as they arise. On the day the poilots did everything correct and so did the crew.
MH17 flew over a war zone, Ukraine. Some people are arguing that they should stop flying over war zones. Qantas has stopped flights in and over Ukraine so why aren't malaysain airlines stopping lights over ukraine. The reason is money. It will be $66 dollars for more fuel adn it will take longer too. Some people are now calling for stricter rules, so flights can't travel over war zones. It would cost airlines more, but would guarantee a situation like this doesn't happen again. The aviation industry is also looking at other ways it can protect passengers. One suggestion is that planes could be fitted with missile defence systems, warning pilots about any dangers coming from the ground.
So what happens to malaysain is unpredictible but planes are are still the safest transport.