Definition of "flyover"

They form part of the vast electrification and reconstruction schemes which have been in hand for a number of years at Liverpool Street, and in suburban Essex, and include the rearrangement of tracks, of which the Ilford flyover forms part; the modern signal boxes, now needed only at key points; the electric control or sub-stations; and a large electric car shed.

1951 January, R. A. H. Weight, “A Railway Recorder in Essex and Hertfordshire”, in Railway Magazine, page 44

As our train to Paris dashed through the labyrynthine flyovers at Porchefontaine, barely a mile from Versailles, the 75 m.p.h. limit was already almost attained.

1961 November, H. G. Ellison, P. G. Barlow, “Journey through France: Part One”, in Trains Illustrated, page 670

Boom Town may not be a definitive text—save that for the historians—but it’s a significant update, one that exchanges the dusty pop-cultural clichés of a “flyover” city for the spark of a sincerely enlightening place.

2018 September 26, Carson Vaughan, “'Boom Town' Explodes the Notion of ‘Flyover’ Territory”, in The Atlantic‎

If Democrats end up flipping state houses in places Trump won in 2016, they will have proved themselves capable of winning in the places coastal elites derisively refer to as “flyover America.”

2018 October 30, Rahm Emanuel, “The Biggest Story of the Midterms Is One the Democrats Aren’t Telling”, in The Atlantic‎