Convair F-106A Delta Darts on the factory production line in San Diego, CA sometime 1957.
The F-106A-CO Production Numbers (102, 121, 122 etc) painted on the tails can match to their tail numbers from my F-106 Aircraft Inventory Database for example 120 is actually F-106A-CO-580763. Early production aircraft with boundary layer fences on the wings before manufacturing removed them and replaced with with leading edge wing slots.