Airline

Usually about 40% of people who've booked tickets don't show up for their flights so they overbook to fill up the plane (Cause planes are expensive to run, especially if it's just transporting like 50 odd people)

i don't know where you got your % but i call nonsense. a fast google search got me numbers like 91% and 94% which sounds much more like what i see on a daily basis.

Your numbers are correct. They generally overbook flights by 10% to 15% in case of cancellations or missed flights. The airlines still make their money as most cancellations are not done before the 24 hour window for free cancellations.

yeah and frequently people who booked and paid for a flight don't get on because of the overbooking policy, which is really a treat when its the international flights, which also don't go out 2-5 times a day like the ones to say, Atlanta or Chicago do. really adds some delight to the already stressful nature of season.