Airline stocks are getting crushed

Shares of major airlines slumped in trading on Wednesday after the Associated Press reported that the Justice Department is investigating whether they colluded to fix prices.

Shares of Delta and American Airlines fell more than 4%. JetBlue slipped more than 5%.

A Justice Department spokesperson confirmed to the investigation to the AP.

According to the AP's report, airlines have removed unprofitable routes, and tried to slow down growth to prop up the prices of airfares since 2008.

The report is based on a document the AP obtained.

Here's a chart showing the dip in shares of some of the major carriers (United, Southwest, Spirit, Delta and JetBlue) on Wednesday: