Palmdale Regional Airport / USAF Plant 42 Airport — Palmdale, United States

Palmdale Regional Airport, coded PMD, shares its runway with USAF Plant 42 in the Antelope Valley of California, a facility deeply tied to American aerospace history. Plant 42 has been used for the assembly and flight testing of major military and experimental aircraft, including Lockheed's stealth programs and Space Shuttle-related operations, making it a significant dual-use site combining sensitive defense manufacturing with limited civilian commercial service. Commercial passenger flights at PMD have been intermittent over the years due to low demand relative to nearby Los Angeles airports. The site remains primarily active as an aerospace testing and production hub rather than a conventional passenger airport.