Southwest Airlines is planning to investigate maintenance issues that have kept an "unprecedented" number of aircraft out of service and prompted flight cancellations as a feud heats up between the carrier and its mechanics' union.
Southwest says that on any given day it plans to have roughly 20 aircraft out of its fleet of about 750 Boeing 737s out for maintenance but that number has more than doubled in recent days. Southwest since last week has canceled more flights than its rivals.
On Wednesday, Southwest had canceled more than 400 flights as snow, sleet and heavy rain crossed the U.S. A day earlier, the carrier had canceled 191 flights, compared with 32 by regional carrier Mesa Airlines and 24 by American Airlines, according to flight-tracking site FlightAware.
Southwest shares ended the day down more than 5 percent on Wednesday after the company trimmed its revenue outlook for the first quarter on a larger-than-expected impact from the partial government shutdown.
The airline declared an "operational emergency" at several maintenance bases last week, and added its Dallas hub to the list Tuesday, telling scheduled mechanics to show up at work or risk termination.