There are as many theoretical answers to this question as there are birds in the sky. "Two possibilities come to mind. One is that they flew into North Las Vegas airport," says veteran KLAS-TV reporter George Knapp. "The other is that they flew into McCarran but it was the executive terminal, the place where many of the private planes are parked and serviced. That part of the airport is currently where a few of the helicopter outfits are headquartered." University of Nevada-Las Vegas Professor of History Eugene Moehring theorizes that charters may have deplaned at what eventually became the Hughes Executive Jet Terminal, "where helicopters are today. [It’s] south and across from Mandalay Bay where the ‘McCarran Field’ arch still stands on the east side of the Strip. That was the original McCarran airport of 1948."
McCarran International Airport spokesman Chris Jones had a few theories of his own. "The building that now makes up a large portion of today’s Terminal 1 opened in March 1963, and most commercial airlines have been based in the Paradise Road vicinity ever since," he wrote us. (Moehring confirms this.) "But for years after that – and even today – there have been some operators who’ve worked from the west side of the air field, or from other different hangars and facilities around the property. Well into the 1980s, the buildings that were later acquired by Clark County to be remade into Terminal 2 (now shuttered) still housed commercial carriers such as Pacific Southwest Airlines, among others."
"When you landed that day, there may have been work going on at the new terminal, so you may have de-planed at another building--perhaps the old Terminal 2 that later handled international flights before Terminal 3 opened," Moehring suggests. "Terminal 2 had a lot of exposed pipes."
"My initial thought was perhaps this person flew through the old Scenic Aviation facility (visible in the attached photo, along the left side of the photo just above the runway)," Jones continues. "It used to house its Grand Canyon tour flights out of a big Quonset hut – which would suggest visible pipes and duct work, as described – before the company was sold to SkyWest in the early 1990s. However, your reader’s words stated that he/she flew to Las Vegas through the facility in question – not merely returned there after taking a tour – which makes me question whether his/her trip may not have involved the Scenic facility after all. There’s been so much evolution at McCarran over the decades that I just can’t pinpoint an answer to this one."
As it happens, McCarran International Airport employs a historian – Mark Hall-Patton – and he offers what may be the definitive answer: "If [your correspondent] flew in before late 1974, he may be remembering the area that is now the A and B gates. The cluster buildings were built between 1970 and 1974, and -- while they were being built -- trailers were used for some of the gate areas. While under construction, it may have looked rather ‘industrial,’ and certainly would not have seen finished interiors until both cluster buildings were completed. Later in the 1970s, it could have been the old terminal on the Las Vegas Boulevard side of the field. That was being used by Hughes Flight Services, and was home to some charter flights."