Southwest Airlines has the most efficient boarding process by far, and it is aligned well with a basic, tiered pricing structure.
I just flew to/from the Caribbean on business on American. They have so many boarding tiers, before the proletariat class is allowed to board. Some aisle seats were filled, before the window people boarded, further jamming up the aisles. I could go on an on, but anyone who has flown knows the experience of inefficiency of boarding. It is like the Greyhound bus culture has sprouted wings.
There is a spoof movie boarding scene with Joe Pesci. He is involved in crime where he has 3 decapitated heads in his carry on. It is quite funny - how he treats the young guy sitting next to him, and then when the flight attendant wants to move his bag.
SW loading is good, but since most find the front of the plane more desireable, there is a jam in aisle at the front. Let me on first and I won’t be slowing things down as I go sit in the back at a window seat.