Sunny 20's

This is a cover for The New Yorker from June of 1927 by H.O. Hofman.  Some of those sort-of-UFO-looking things are blimps/zeppelins/airships... with little biplanes in amongst them.  Here in the midst of the Roaring 20's we have much of the rest of the solar system there, giving a "sky's the limit" kind of sentiment.