Star Ariel was an Avro Tudor Mark IVB passenger aircraft owned and operated by British South American Airways (BSAA) which disappeared without a trace over the Atlantic Ocean while on a flight between Bermuda and Kingston, Jamaica, on 17 January 1949. The loss of the aircraft, along with that of BSAA Avro Tudor Star Tiger in January 1948, remains unsolved, with the resulting speculation helping to develop the Bermuda Triangle legend.

The Avro Type 688 Tudor was a British piston-engined airliner based on Avro's four-engine Lincoln bomber, itself a descendant of the famous Lancaster heavy bomber, and was Britain's first pressurised airliner. Customers saw the aircraft as little more than a pressurised DC-4, and few orders were forthcoming, important customers preferring to buy US aircraft. The tailwheel undercarriage layout was also dated and a disadvantage.