Lawmakers are concerned about safety lapses at Southwest and other U.S airlines, The Wall Street Journal reported Saturday.

The House Transportation and Infrastructure Committee heard from witnesses Thursday, including the Department of Transportation's inspector general and the union that represents FAA safety inspectors.

A Senate aviation safety and security subcommittee is planning to also investigate airline safety lapses.

Sen. Jay Rockefeller, the West Virginia Democrat who heads the panel, said revelations of Southwest's safety issues "have thrown a cloud over" the FAA.

He said lawmakers will pursue "a comprehensive review of the FAA's safety operations" and likely resulting in "additional steps to make sure our aviation system remains the safest in the world."