Originally Posted by
3Cforme
Trying to keep this DL-specific, it seems DL likes to use a single number for some domestic-international and international-domestic (but I'm challenged to find any flight numbers at the moment).
DL 30 (DFW-ATL-LHR) comes to mind, though it seems it hasn't been used as such in the past few weeks at least.
Update: I see DL 32 is now being designated as the direct flight between DFW and LHR (via ATL).