By Amanda Weston

Southwest Airlines declared an "operational emergency" as the reason it has been forced to cancel hundreds of flights this week, but the problem may be human rather than mechanical.

"It's certainly an odd term for them to call this an 'operational emergency,'" Brian Sumers, senior aviation business editor at Skift, told Cheddar Wednesday. "It's something that probably makes a lot of passengers nervous."

"Instead of an operational emergency, let's call it what it is," he said. "It's a labor dispute."

Sumers said Southwest ($LUV) has been trying to negotiate a new contract with its mechanics for six years ー what he calls "an obscene amount of time."

"Sometimes when this happens, the people in the labor dispute, in this case the mechanics, maybe they don't work as hard," Sumers said. "Maybe work takes a little bit longer, or more mechanics than usual call in sick. Maybe they're trying to prove a point. This is what Southwest alleges."

Southwest is now requiring workers to provide a doctor's note if they call in sick. Those who refuse to come in could be at risk of being fired.

"Southwest usually has about 20 planes out of service for mechanical problems on any given day," Sumers said. "Right now they say twice as many are out of service. They're not really sure why. They need all these airplanes in service because in the interim, when they have twice as many planes out of service, it means they have to cancel and delay more flights."

The operational emergency comes just a few weeks after the longest government shutdown in U.S. history, which took a heavy toll on the aviation industry. In January, at least four major airports suffered delays because of an increase in air traffic controllers calling in sick. Many TSA agents also stayed home or had to work without pay.

But Sumers doesn't believe Southwest's current situation is necessarily related to the shutdown.

"This Southwest thing is probably a little bit difficult and I think there's just heightened tensions on both sides," Sumers said. "As somebody who follows this closely, I do hope both sides can agree on a new contract soon. I think it would be good for everyone, including passengers."

For full interview click here.