Originally Posted by
ctownflyer
Do you have a source for this or just personal experience?
Both, but YMMV. I have flown with carseats in lie-flat BE on both DL's 777 and 767, and only once had an FA challenge it (in a 767). After considerable debate (involving FAs, GAs, the pilot, and a redcoat), an off-duty pilot who happened to be seated in the cabin observed that the seatbelt could be deactivated with the proper extender. I've had this confirmed to me by FAs here on FT (although the actual documentation cited was from the procedures manual of another operator).
That said, I've never actually seen said extender. In most cases, the FAs didn't raise an issue with the seat. In the case mentioned above, they couldn't locate the extender either on the aircraft or on the ground (LAX, not a small station for DL) so the FAs allowed the seat, but required the infant sit in a parent's lap during takeoff and landing.
I suppose it is possible that the airbag can be disabled on the 767 (and 747) but not the 777--that would not be inconsistent with the facts as I have experienced them, and does align with the text you point out on the website (which is fairly new, as I have never seen it before).