All their stated reasons are simply BS excuses. Come on. We all know the real reason: The airline(s) want to get their beaks wet in the deal. Either by a contract that gets them yearly guaranteed revenue for doing nothing, or by some kind of deal where the agent guys promise to steer users to one airline preferentially instead of finding the best deal (or users' other preferences).

If Meta or Claude or whoever came to an airline offering that kind of deal, they'd build an MCP in a week and solve the very simple regulatory issues - simply add a skill that shows the exact same UI of "promise you have no swords, machine guns or bombs in your luggage") to the user that the airline's own site uses.

Until that happens, they'll just ban them.