Originally Posted by
The _Banking_Scot
However both bim and CO/UA fly from Terminal 1 ( UA moved from T3 to T1 a while back) which save a bit of time
Minor point of clarification (though it doesn't really affect the OP's husband): UA operates from both T1 and T4 at LHR. The legacy UA flights, of which SFO-LHR is one, are out of T1 while the legacy CO flights are out of T4. In this case the passenger will re-clear security in T1 and not need to transfer terminals, saving quite a bit of time.