The airline had been saying that it would scrub 850 flights on Wednesday.
Added to Tuesday's 460 cancellations, that could bring the two-day total to around 1,500 lost flights.
Federal inspectors found problems with wiring work done two weeks ago, although the airline says passenger safety was never jeopardized.
Airline officials said the flights would have averaged more than 100 passengers, meaning that more than 100,000 travelers could have been left scrambling to book new flights.