It’s the longest string of monthly decreases since 2001 and 2002, when traffic numbers fell for 15 consecutive months.

For the year, traffic is down 7.1 percent to about 40.9 million arrivals and departures through November.

Every one of the top five airlines at McCarran showed a decrease, including Southwest, which is by far the largest carrier of Las Vegas-bound passengers.

Even Las Vegas-based Allegiant Air saw its traffic in and out of McCarran fall 8.6 percent, an anomaly for an airline that’s more accustomed to double-digit increases.

The biggest percentage decline in November belonged to US Airways, which saw traffic into and out of Las Vegas fall 31.4 percent to 466,555. For the year the Phoenix-based airline is down 23.6 percent to about 6.7 million arrivals and departures.

Southwest traffic fell 10 percent in November to about 1.1 million arrivals and departures. With 14.5 million passengers into and out of McCarran in the first 11 months of the year, Southwest is 1.8 percent below the pace it set in 2007.

Delta fell 7.3 percent in November to 189,345 arrivals and departures and is down 4.2 percent for the year to 2.2 million.

American fell 4.6 percent for the month to 170,610 and for the year the airline is down 0.1 percent to about 2 million.

Allegiant, which specializes in flying leisure visitors from small towns to Las Vegas, Florida and Arizona, posted an 8.6 percent decrease to 137,405 arrivals and departures at McCarran in November.

For the year, Allegiant is up 1.5 percent through November to almost 1.6 million arrivals and departures.

Traffic at terminal two, which is where international flights arrive and depart, was down 29.5 percent in November to 142,617 arrivals and departures. For the year, terminal two traffic is down 1.4 percent to about 2 million arrivals and departures through November.

Contact reporter Benjamin Spillman at bspillman@reviewjournal.com or 702-477-3861.