It hasn't disappeared in British (and related) English. What is called an 'airplane' in US English is an 'aeroplane' in British English. Ditto 'aerofoil', etc.

It hasn't disappeared in British (and related) English. What is called an 'airplane' in US English is an 'aeroplane' in British English. Ditto 'aerofoil', etc. 'Aero' is a Greek prefix pertaining to 'flight'. (And also to 'air') The two dots above a letter indicate that the two vowels are pronounced separately, rather than as one sound. As also seen in "The first Noël the ......", etc.