SWBKCB has it - it's the unbelievable drive of customers to save a quid by driving halfway across country to leave in the middle of the night in a plane that yo'd be fined for operating if you crammed in livestock in the same way.
Which is the most successful new airline in the past 40 ears in Europe - Ryanair - famous for doing NONE of the things that rog747 dreams of
"If I did (I likely would be quite mad I hear you all cry) then I would like to look at starting an Airline that goes back to basics offering Passengers a decent product, and showing them some respect.
IE; Hold Luggage and seat allocation included, hot meals on flights sat in a Comfy seat, all with decent leg room."
That's what a bundle of people have tried - and that's why they fail - they underestimate just how low customers are wiling to go