AvGeek1
Given that Americans only European route is LAX to Heathrow i doubt Manchester comes close to being in their thoughts.
Actually LAX- Europe is rather poorly served by US carriers
Delta - None on own metal - AFKL and VS codeshares
American - Just LHR and BA with seasonal IB codeshare
United- Also just LHR with LH Group codeshares -SFO is their West Coast hub BTW
Oh and Air New Zealand to LHR
The alliances are represented largely by the Europeans .
Then you have the Flexible Fares none aligned Thomas Cook/Condor, Norwegian and XLF from Paris.
So the only candidate is Virgin Atlantic and thats quite likely in the new term.
Now for Miami now American does connect with London of course and Madrid Barcelona Milan and Paris the later largely ethnic traffic .
Problem with Miami is it's sometime seen as a seasonal route and it has previously operated in the winter from Manchester - That said i think the Americans miss read the UK market and it would actually do better in the northern summer !
Could it return maybe.
The third and in my opinion most likely AA addition remains Dallas