DALLAS — Today, in 1951, the American-built, improved high-elevation performance 44-seat Convair CV-340 made its maiden flight.

The aircraft was a stretch of the popular CV-240, one of the most advanced short-haul airliners of its day. The 240 was built following a requirement from American Airlines (AA) for a replacement for its fleet of Douglas DC-3s. The 340 had a longer fuselage, a bigger wing span, and upgraded engines.

Originally dubbed the "Super 240," United Airlines (UA) ordered 52 of the type, which remained in service with the carrier for 16 years. Orders from Braniff (BN), Continental (CO), Northeast (NE), National (NA), and Delta Air Lines (DL) followed.

In Europe, KLM (KL) used the type on its short-haul services from 1953 until 1963.

"Owl" Flights

Delta Air Lines (DL) had originally ordered ten Martin 2-0-2s but decided to swap them for the Convairliner. The carrier then inherited a further ten of the type after merging with Chicago and Southern Airlines on May 1, 1953. It used the -340 on its nighttime "Owl" discount red-eye flights between Chicago and Miami.

The aircraft proved so popular with airlines and passengers alike that Convair went on to develop the larger CV-440 Metropolitan.

Many CV-340s were converted to the new variant, which had seating for 52 passengers. Improved avionics, soundproofing, and max take-off weight were just some of the upgrades.

Orders came from many operators of the -340, and in Europe, the type was used by Finnair (AY), Swissair (SR), Lufthansa (LH), and SAS (SK).

Featured image: United Airlines dubbed its CV-340s as 'Mainliners'.