Yes. The "daito" sword - which is the longer katana - is certainly uniquely Japanese. Daito Ryu and Aikido movements as not just based on universal swordmanship, but specifically the katana, and more specifically the daito katana. Daito Ryu....sorta adds up...
Is it still Aikido if you take away the Japanese Daito Katana?.
This should really be a different thread, but I'll bite here. I have never seen any convincing evidence that Aikido movement is based on any style of kenjutsu. If there ever was a connection, I think it was lost a long time ago. I think Aikido movement is based on what works well with the human body at the ranges that Aikido is practiced.