Are you looking for ET or CE? Looking at ba.com , searching for 1 person I see 3 flights available in ET, FRA-LON, 2 to LCY and one to LHR. On aa.com I see 2 flights available, the same 2 flights into LCY as ba.com shows. I don't know why the LHR flight isn't showing up but it looks like aa.com is having a problem because none of the many CE flights into LHR that are available aren't showing either. You might want to call.