Pan Am Flight 103 (PA103/PAA103) was a regularly scheduled Pan Am transatlantic flight from Frankfurt to Detroit via a stopover in London and another in New York City. The transatlantic leg of the route was operated by Clipper Maid of the Seas, a Boeing 747 registered N739PA. Shortly after 19:00 on 21 December 1988, while the aircraft was in flight over the Scottish town of Lockerbie, it was destroyed by a bomb, killing all 243 passengers and 16 crew in what became known as the Lockerbie bombing. Large sections of the aircraft crashed in a residential street in Lockerbie, killing 11 residents. With a total of 270 fatalities, it is the deadliest terrorist attack in the history of the United Kingdom.

Lockerbie is a town in Dumfries and Galloway, south-western Scotland. It is about 120 km (75 mi) from Glasgow, and 25 km (16 mi) from the border with England. The 2001 Census recorded its population as 4,009. The town came to international attention in December 1988 when the wreckage of Pan Am Flight 103 crashed there following a terrorist bomb attack aboard the flight.