Southwest, Tesla, Las Vegas Sands
A Southwest Airlines Co. Boeing 737 passenger jet pushes back from a gate at Midway International Airport (MDW) in Chicago, Illinois.Luke Sharrett | Bloomberg | Getty ImagesCheck out the companies making the biggest moves premarket:Southwest — The airline dropped 2.1% after reporting a $220 million loss for the fourth quarter after the holiday meltdown cost the company millions in expenses and drove up expenses.Comcast — The media company reported fourth-quarter earnings that beat Wall Street's expectations, with earnings…