Boeing released short videos on 7 June 2021 showing a Boeing
MQ-25 T1 test unmanned aircraft refuelling a F/A-18 Super Hornet.
Boeing claim the MQ-25 is the first unmanned aircraft to ever refuel
another aircraft - piloted or autonomous - during flight.
30 second video here :-
https://youtu.be/q2uGkF2J1Y0
2 minute video here :-
https://youtu.be/GqZOaUpORjo
Boeing MQ-25 information page :-
http://www.boeing.com/defense/mq25