system

I’m no lawyer, so…
IF Boeing and Southwest have such a business arrangement…
What laws have they broken by having said arrangement?

system

That suit sounds contrived sour grapes to me. The economies derived from flying and maintaining a single aircraft type are huge. That alone would be enough motivation to restrict their fleet to the 737. SW has been one of the few profitable airlines through hard times and good times, because of their good management and smart, innovative policies.