I mean in the days of transatlantic flying. No westbound heavy going transatlantic can get off the short IIRC. Northwest once got a 747 off 21 but they only went as far as SNN back then. You would not want to land a heavy 747 on 21 as it would end up in the retail park!
So Cargolux could do PIK-LUX but likely not land from the US in the first place due landing distance available, not to mention no ILS.
Does PIK still have SRA?