Major air traffic control staffing shortages have snarled thousands of flights as the US government shutdown causes mounting travel woes and alarm among airline officials.

The Federal Aviation Administration said on Saturday there were air traffic control staffing issues affecting 42 airport towers and other centres and delaying flights in at least 12 major US cities - including Atlanta, Newark, San Francisco, Chicago and New York. Flights crossing six different high-traffic areas were also facing delays.

Some 1500 flights were cancelled and 6000 flights were delayed on Saturday, compared with Friday when 1025 were cancelled and 7000 were delayed.

Airline officials privately said the number of delay programs made it nearly impossible to schedule and plan many flights and expressed alarm

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