people misunderstood Elijah,he was not talking about these yellow asians he was talking about original asiatic black man,many are still there,tough they have been wiped out by mongolians:Ahh here is the riddle ... which takes us back to the genetic theory as it was ... did the Asian come from African even though their is no genetic associate to my knowledge?
Here is a picture of the Khoisan's:
Could what Elijah Muhammad been talking about was the Khoisan people? As you said, "Elijah Muhammad said that the people who built the Mother Plane(UFO), looked Chinese".
Did you know that the Khoi & Sans people which are one people now called 'Khoisan' are amongst the oldest people on the planet?
Elijah Muhammad could have definitely been on to something with the exception of the Mother ship being created near Japan unless their is some genetic connection between the Khoisan's and Japanese.
Peace and Blessings
original japonese aka The Ainu
mixed marriage change this people phenotype,here a modern ainu:
^^but you can still see the presence of blackness in this man