Allentown Queen City Municipal Airport (XLL) is located in Allentown, Pennsylvania and is the main airport serving Lehigh Valley, Pennsylvania. The airport is also known as Lehigh Valley International Airport, which was its original name, but was changed in 1960 to reflect the nickname of the city, "Queen City of the Lehigh Valley".

The airport was established in 1929, when the city of Allentown purchased a plot of land to build the airfield. The original airfield was only about one-third of the size of the modern airport and was used primarily for small plane flights. In the 1940s, the airport was used by the United States military during World War II, and after the war, it was expanded to its current size and became a commercial airport.

The airport code XLL was assigned to the Allentown Queen City Municipal Airport in the 1950s by the Federal Aviation Administration. The code is made up of the letter X for the United States, followed by two letters that denote the area of the airport. The letters LL stand for Lehigh Valley, which is the region in which the airport is located.

Today, Allentown Queen City Municipal Airport serves approximately two dozen flights daily, with most of the flights being operated by American Airlines, Delta Airlines, United Airlines, JetBlue Airways, and Allegiant Air. The airport also offers flights to several other destinations, including Charlotte, Chicago, Philadelphia, Detroit, and Washington, DC.

Allentown Queen City Municipal Airport is an important part of the area's transportation infrastructure, and it has helped to make the Lehigh Valley a popular destination for air travel. The airport has also been the site of many major events, including the NCAA Division I Men's Basketball Tournament, the Little League World Series, and the PIAA State Wrestling Championships.

The Allentown Queen City Municipal Airport provides a convenient and easy way for travelers to access the Lehigh Valley and beyond. With its modern infrastructure and convenient location, the airport is an important gateway to the region and to the world.