There are quite a number of those arrows still in existence in the southwest. The last remaining of the arrows in the whole of the upper midwest is located just a few miles from my house and is in the front yard of a farm where the owners, probably back in the 60's or 70's, put in a basketball hoop at the base-end:
https://www.google.com/maps/place/A...b6662a3c71d565!8m2!3d44.8188933!4d-92.9117659
That particular arrow, which used to have a beacon, was the last of a long line of arrows/beacons that led air mail pilots into the Dowtown St. Paul Airport (today KSTP) on routes from Milwaukee and Chicago. The original beacon tower, erected near the St. Paul Airport in 1929, located within Indian Mounds Park, still stands and has been restored and painted in the original yellow/black scheme it originally had:
https://upload.wikimedia.org/wikipedia/commons/4/42/Beacon_tower,_Indian_Mounds_Park.jpg
A couple of websites on the 1920's airway navigational arrows and beacons.
http://www.dreamsmithphotos.com/arrow/index.html
https://sometimes-interesting.com/2013/12/04/concrete-arrows-and-the-u-s-airmail-beacon-system/