Factual error: When the hitman shoots the Mustang's windshield, the damage is not consistent with a shotgun blast at close range. The windscreen is actually hit in two separated areas. Winchester would be very unhappy if their guns really shot like this.
Factual error: After the mid-point chase scene, Lt Bullitt drives to an airport hotel identified as the "Thunderbolt hotel in San Mateo." The hotel [originally 'Thunderbird' in the early '60s, renamed 'Thunderbolt', then 'Clarion', finally 'Aloft' in 2012.] is located adj the SFO runways at 401 E.Millbrae Av Millbrae, not San Mateo.
Answer: Airport security in the late 1960's was not nearly as thorough as it is in present day. Metal detectors didn't become commonplace at airports until the early 1970's.
BaconIsMyBFF
It was the D.B. Cooper hijacking of a Boeing 727 commercial jet in 1971 that radically changed how airport security was handled. Before that, there was virtually little to no pre-boarding security checks.
raywest