I think you might get some mileage out of skimming the wikipedia article on "Perfect Competition".[0] While "free markets" are a bit of an ill-defined, politic

I think you might get some mileage out of skimming the wikipedia article on "Perfect Competition".[0] While "free markets" are a bit of an ill-defined, political term, "perfect competition" is well-defined, in a mathematical sense, well-studied in Economics, and generally regarded as a good thing. But (as you'll read in the wikipedia article) there are a number of required conditions for it. So good regulations could help ensure those conditions are met. For example, one of the conditions is "no externalities", which are things that affect 3rd parties not involved in the buying/selling decision. Pollution could be relevant to airlines; perhaps one airline can offer cheaper tickets by burning dirty and dumping soot all along the way. That's not perfect competition because it affects all the people who suffer from the pollution, but not the person buying the ticket (who naturally would be incentivized to buy the cheaper ticket). But if the government mandated pollution standards that protects all the non-flyers, and that all the airlines are subject to, then it's a fair competition on price again. [0] https://en.wikipedia.org/wiki/Perfect_competition https://en.wikipedia.org/wiki/Perfect_competition