Florida Rep. Charlie Crist has asked the U.S. Department of Transportation to consider investigating United Airlines after receiving complaints the carrier was "gouging" customers trying to escape powerful Hurricane Irma.

Consumers this week complained that airfares out of the state had skyrocketed as they attempted to fly out of Florida before the Category 4 storm hits the state this weekend.

High prices close to a departure date with minimal availability are not unheard of under such conditions. However, United Airlines capped fares at $399, as did its competitor Delta Air Lines. Other rivals JetBlue and American Airlines set a maximum price of $99 for economy-class seats out of South Florida airports. These airlines have also added flights to meet a surge in demand for seats for flights out of Irma's path.

"While I understand the fundamental economic principle of supply and demand, no company engaged in interstate commerce should exploit an emergency to take advantage of the people," Crist, a Florida Democrat, wrote to Transportation Secretary Elaine Chao in a letter dated Sept. 7.

Airlines have canceled more than 4,000 flights ahead of the storm, which the National Oceanic and Atmospheric Administration expects to make landfall in Florida as early as Sunday.