MiB is not interested in the plane. THAT is not what will get him off the Island.
Theory: MiB doesn't need a plane - he needs the regular humans on the Island (candidates, Widmorites, leftover Others) to destroy each other as he told Jacob they always do. He NEEDS Sawyer to be lying and backstabbing; Sawyer isn't one step ahead of MiB, he's doing exactly what MiB wants to happen. MiB needs Jacob to be PROVEN WRONG. Once Jacob is proven wrong, then MiB can leave the Island forever.
Remember the opening conversation of The Incident...we all heard MiB and Jacob talk about bringing people to the Island. Jacob says "it only ends once". This is that once. The final six candidates that Jacob needs to be proven right.
MiB is now saying it's about the plane, but it's a lie. What he really needs is for the people "to come, to fight, to corrupt", to have it "always end the same". All of this stuff about the plane and getting people together is so he can (once and for all) prove Jacob is wrong and he is right. He is waiting for people to become selfish, do what is in their self-interest over the needs of their friends, etc. Then MiB wins.
Do you agree?