Obligation to have a starlink terminal on the plane to enable communication with the radio tower. This comes with the added bonus of enabling Elon to sell Starlink internet in-flight.

Prescribed users will get access to net and non-users will get forked as per-usual. But with an Elon branded fork instead.

I also expect he's eager to make it proprietary. That way it would then force all other airlines that route through the USA to have a Starlink terminals too.