Ah yes, what a convoluted world IP and patents can be. The drug companies are very good at "varying" the design of a medication to claim a change to the patent and so prevent others using the compound. In their business it is hard to produce a medication that performs the same as a competitor without using the patented compounds and copyrighted IP.
Even if Boeing extend the patent through variation of the existing design it would not prevent Airbus now designigning a steerable body gear as long they ensure they do not use specific details of the Boeing designs which (presumably) would still be protected IP in the form of copyright.