Stay off Russian and African (Congo region) airliners. They are infamous for having poor safety standards and very rarely enforce them. If its an airline you haven't heard much about, I would do some research on the age of their fleet. How old are their airplanes? How much money does the airline make? How long have they been in business? Why is that important? Older airplanes require more frequent maintenance and they are expensive to operate. If the airline isn't making money, how are they affording to maintain their airplanes? Air travel is very safe, however, never assume every airline out there is operating at 100% in regards to safety.