How do some travel websites offer cheaper tickets?

Question

How do some travel websites offer cheaper tickets?

Answer 1

Without specifics, its hard to tell, but the majority of them are what are called consolidators.  What they do is purchase blocks of tickets from the airlines at a discount for the bulk purchase and re-sell them.  Since they pay less, you can pay less.  There's more to the market than that, but thats the basic idea.