On January 9, 1973, the federal government fined the Marquette Airport, along with only three others throughout the rest of the country, for failing to comply with a mandated Federal Aviation Administration anti-hijack program. Faced with continuing $100-per-day fines, Marquette airport officials, who had claimed the regulations were too strict to implement, reluctantly hired armed guards and installed required metal detectors.
Source: Mich-again’s Day