Two Global Hawks have flown in formation as a precursor to actual aerial refueling between the two aircraft.
Unlike the normal probe-and-drogue refueling procedure, the tanker is positioned behind the receiving aircraft and fuel is pushed uphill to the receiver once the tanker plugs into the drogue.
[thumb]http://www.aviationweek.com/Blogs.aspx?plckBlogId=Blog:27ec4a53-dcc8-42d0-bd3a-01329aef79a7&plckPostId=Blog:27ec4a53-dcc8-42d0-bd3a-01329aef79a7Post:60dec69a-7eff-432b-998c-cacd04669134[/thumb]