Europe's Airbus said on Friday it was ordering immediate repairs to 6,000 of its widely used A320 family of jets in a sweeping recall affecting more than half the global fleet, threatening upheaval during the busiest travel weekend of the year in the United States and disruption worldwide.

The setback appears to be among the largest recalls affecting Airbus in its 55-year history and comes weeks after the A320 overtook the Boeing 737 as the most-delivered model. At the time Airbus issued its bulletin to the plane's more than 350 operators, some 3,000 A320-family jets were in the air.

The A320 was launched in 1984 at a time when many questioned whether Airbus would last another decade after painfully launching two wide-body jets. It first flew three years later.

Airbus engineers in Toulouse, France, gambled on introducing fly-by-wire computer controls for the first time to a mainstream airliner, a pioneering technology that faced resistance from unions and some carriers but later became widely accepted.

Airbus is now expanding production in the U.S. and China.