Actually, IMO AA will be more likely to pursue a BOS-BRU service than DL because of the SN codeshares out of BRU. BRU is getting crowded: current service includes AA's ORD and JFK; CO's EWR; DL's JFK and ATL; and UA's IAD. Soon NW will add DTW-BRU and there are strong indications that US will be adding PHL-BRU next summer. In DL's case, JFK is already pretty marginal in terms of loads (it is one of DL's worst performing TATL routes out of JFK) so I doubt that DL will be adding a third BRU route (also don't think that DL's first TATL route out of BOS will be BRU - perhaps when the ex-TW 752s from AA/ILFC arrive, which won't be introduced into summer TATL service until 2008).