Boundary Bay Airport or Vancouver/Boundary Bay Airport (IATA: YDT, ICAO: CZBB) is located beside Boundary Bay and 2.5 nautical miles (4.6 km; 2.9 mi) east of Ladner in Delta, British Columbia, Canada, 8.5 NM (15.7 km; 9.8 mi) south southeast of Vancouver and close to the Point Roberts-Boundary Bay border crossing. The airport, which opened on July 11, 1983, serves mostly general aviation and includes facilities for aircraft maintenance, flight training and parking. In 2020 and 2021, Boundary Bay airport was ranked as the busiest airport in Canada by aircraft movements.

The airport is classified as an airport of entry by Nav Canada and is staffed by the Canada Border Services Agency (CBSA). CBSA officers are available on call to handle entry for aircraft carrying no more than 15 passengers.

The airfield was originally built in 1941 as Canadian Forces Station Ladner to teach Royal Canadian Air Force and Royal Air Force recruits to be pilots in the Second World War. Operational squadrons operated out of Boundary Bay to provide air defence support against a potential Japanese invasion until early 1944. During the war, more than 6,000 students and personnel passed through the station. After the war, the base was no longer required, and the airfield was decommissioned by the Royal Canadian Air Force in 1946 after it served as a demobilization centre for troops returning from the war.

In the late 1940s, the site was transferred to the Royal Canadian Corps of Signals and became a signals intelligence station under the name Vancouver Wireless Station. The station was responsible for monitoring Soviet Union military communications at the height of the Cold War and played an important role for gathering communications from the Soviet Union and its fleet. A 40-hectare residential community was developed that included amenities such as a grocery store, social club, gymnasium and a sports field. Remnants of this community are still present today as the North 40 Park Reserve, an off-leash dog park and walking trail.

When the armed forces was unified in 1968, the station's name changed to CFS Ladner. The station eventually closed in 1971 due to the installation of nearby power lines in Ladner that made gathering signals difficult.

Following the closure of CFS Ladner, the site was used by the community of Ladner for picnics, public fairs and auto racing.

By the mid-1970s, when it became obvious that Vancouver International Airport could no longer sustain both general aviation and heavy commercial traffic, Transport Canada explored several options and determined that it was most economical to reactivate Boundary Bay as a reliever field to handle general aviation aircraft. The airport underwent restoration, and on July 11, 1983, two of the three runways were reopened as Boundary Bay Airport. A new control tower was built to the west of the field and air traffic services were provided. The remaining runway was made available for driver training and other events, until it became hangarage options for privately owned aircraft.

The field was initially owned and operated by Transport Canada until it was sold to the City of Delta for a nominal fee of $1. Operations and development of the airport was contracted out to a third-party, but the facilities degraded over time until the municipal government vacated its contract with the management company.