Gwynne Shotwell held a media roundtable last week, and the best piece of info is this, thanks to Sandra Erwin of SpaceNews:
Shotwell said many of the Starlink features are being tested by the U.S. Air Force Research Laboratory under a program called Global Lightning. SpaceX in December 2018 received a $28 million contract to test over the next three years different ways in which the military might use Starlink broadband services. So far, SpaceX has demonstrated data throughput of 610 megabits per second in flight to the cockpit of a U.S. military C-12 twin-engine turboprop aircraft.
That’s some serious speed.