Google has Project Loon which sounds vaguely similar. In theory you could have a faster transatlantic signal path by putting microwave relays on blimps at the right altitude.
They have to maintain steady position (impossible for planes).
Also, the weather over the Channel can be quite unforgiving.
Drones are not the end of the line, though. A quick Google search for "hft neutrino" shows how creative these guys could be in their insatiable quests for shaving off microseconds.