BEF

The British Expeditionary Force refers to the British Army Forces on the European Continent, and the many allied forces from elsewhere around the world (AU, ZA, CA, PT, NZ) who organized with them. For some of this time, Gen Douglas Haig was in charge of the BEF and he shows up in Howlett, 2021. The same term, BEF, refers to the same kinds of forces in WWII. Numbered armies, the First through Fifth, were in this force. The en.wp article on the BEF in WWI makes no reference to aerial forces.

Source: w:British Expeditionary Force (World War I)